A Comprehensive Review on Thin-Film Polymer Solar Cells in UAV Technology

2.1. Experimental UAV Models Incorporating Solar Technology

The paper by (Caner İLHAN) highlights the environmental urgency to shift away from fossil fuels and addresses the potential of solar-powered Unmanned Aerial Vehicles (UAVs) as a sustainable alternative in aviation. The study aims to detail a conceptual design methodology to maximize the UAV's operational efficiency, considering the complex interplay of aerodynamics, structure, and performance requirements for solar integration. The design process follows a methodical strategy, starting with a presizing phase to estimate preliminary dimensions and weights. Key decisions involve selecting components based on efficiency and weight minimization. Monocrystalline silicon cells were chosen for their high efficiency (up to 23%). Lithium-ion batteries with a high energy density of were selected. Maximum Power Point Tracking (MPPT) technology is incorporated to maximize energy harvesting and transfer to the battery. The conceptual design phase used a constraint analysis (represented via a MATLAB-generated graph) to optimize power-to-weight ratios and wing loading. The wings are designed to house solar cells over, which is calculated to yield a net power output. The design uses the Eppler 197 airfoil with no taper, zero incidence, and zero dihedral to simplify cell placement and eliminate shadow effects.

The paper by (Dr. Raghvendra Tiwari) focuses the rapidly growing UAV market and the increasing demand for long-endurance missions (e.g., surveillance, search-and-rescue). Integrating solar energy is presented as an innovative and sustainable solution to provide continuous energy, reducing reliance on traditional fuel or battery systems and decreasing operational costs and environmental impact. The basic concept is that solar panels charge a rechargeable battery while the drone is exposed to sunlight, enabling extended flight. The core approach is to utilize a Hybrid System of solar cells and a battery to supplement power and reduce battery dependence. The methodology includes MATLAB simulation of the PV cell and battery integration circuit to analyze the system's performance and characteristics like State of Charge (SOC) under varying conditions. Polycrystalline Silicon panels are used, typically offering efficiency and being suitable for extreme weather conditions. For a small prototype, a total solar output of was calculated from an area. Lithium-polymer (LiPo) batteries are commonly used due to their high energy density and lightweight nature. The system incorporates essential drone components like the Flight Controller, Electronic Speed Controllers (ESCs), motors, and a Power Distribution Panel. The Photovoltaic cell and battery integration is shown in Figure 1.

This paper by (Tomar) explores the integration of solar power in UAVs to enhance flight endurance and enable sustainable, long-duration operations in aerial robotics. The research is motivated by the depletion of fossil fuel reserves and the environmental costs associated with their use, prompting a shift toward renewable energy like solar power in the aviation sector. The design of a solar-powered UAV, addressing the unique challenges compared to traditional aircraft, such as the dependence on latitude, weather, and solar intake for factors like solar panel size and battery capacity. The study factored in flight altitude, latitude, and time to analyse available solar irradiation. Based on the annual solar irradiation map of India, a reference value of was chosen for most regions to ensure optimal UAV performance. Minimizing weight is crucial for solar-powered UAVs due to the lower efficiency of solar cells, as increased weight directly correlates to higher power consumption. The study yielded an R-value (Solar Cell Area/Wing Area) of 0.65. The wing structure design focused on optimizing the number of solar cells and reducing complexity. The taper ratio and angle of wing incidence were kept at 1 and 0, respectively, to maximize cell utilization and avoid shadowing. The total area available for solar cells on the wing was calculated to be 2.86 m². The SPUAV model developed by the researchers is showcased in Figure 2.

This paper by (Asutosh Pati) focuses to achieve continuous flight for more than 24 hours using only solar energy. The methodology focuses on ensuring the solar-powered UAV achieves perpetual endurance, meaning it collects more energy than it loses during a day. The power needed for steady level flight was determined to be at least 20 kW. Based on the power requirement, the energy needed for continuous night flight was approximated at 240 kW-hr. Sunpower A-300 cells were chosen for their high efficiency. The area needed to produce was calculated using irradiance models. The Stender model, suitable for solar-powered UAVs, was used to calculate the airframe weight. The wing planform and control surfaces were designed, specifying the aspect ratio, taper ratio, and aileron size, with material choice considering Carbon Fiber Reinforced Polymer (CFRP). The paper concludes that the application of high-altitude long endurance solar UAVs is potentially very large, covering areas like weather surveillance, natural disaster study, and fire direction.

This paper by (Dr. Vivek Sharma) details the development of a Solar Powered Quadcopter Drone as a solution to the limited flight time and battery related constraints of conventional drones used for surveillance and monitoring. The drone is a quad rotor design, making use of four high-powered drone motors with propellers to provide the necessary lift. The drone uses 4 high-powered drone motors which are responsible for flying the drone by spinning the propellers in the correct direction with a three-phase current. Generally, a motor of 12,000 rpm rating is used for flight. The propeller generates air flow and spins, creating a pressure difference for lift. A CKIOS 80-watt Polycrystalline Silicon Solar Panel is used. The solar panels are integrated into the drone body for high-efficiency charging. The drone uses an RC remote controller (like the TX12 model shown) with a radio transmitter to perpetually read stick input and transmit control commands to the onboard RC receiver. A Wi- Fi camera is integrated and can be monitored via an Android smartphone using a Wi-Fi connection. The system architecture includes a Power Management System and Basic Electrical Components. Power Management System (PMS) stores power from the solar panels in the battery. It includes a PV Module (solar panels) that captures and transforms solar power and uses a Battery Module for power storage. An Arduino UNO Microcontroller is connected directly to all modules of the PMS, passing signals to other electrical components and sensors. Basic Electrical Components includes four motor drivers (Motor Drive 1-4) that receive power from the battery and operate the four motors (Motor 1-4) based on instructions from the microcontrollers and the flight control unit. The flight control unit uses an Arduino Nano Microcontroller.

The paper by (Franklin Salazar) details the optimization of the solar energy storage capacity for a fixed-wing Unmanned Aerial Vehicle (UAV) designed for long-endurance monitoring and video surveillance applications. The primary goal is to increase the UAV's flight autonomy by integrating a photovoltaic (PV) solar system while minimizing the battery capacity to reduce the overall aircraft weight. The research focuses on a fixed-wing, glider-type UAV prototype whose design was optimized based on the meteorological conditions of Ambato, Ecuador. The UAV integrates two main systems that draw continuous power are Telemetry (Pixhawk 2.1, Radio 3DR, GPS) and Video System (GoPro Hero 6 Black, Video Transmitter). Propulsion devices include QA2825 engine and DS-843MG servomotors. The telemetry and video systems consume 1117 mA. The average total consumption during flight is calculated at 20.01 Amperes. The Photovoltaic system is designed to act as a backup to minimize battery discharge and extend flight time. 48 C60 monocrystalline solar cells (125x125 mm) are consolidated in series along the fixed wing. The system is capable of supplying a total peak power of 178.56 W. The two photovoltaic modules, including the protective plastic layer and welding connections, add an extra 690 g to the aircraft's weight. The storage system's capacity was optimized using an objective function (OF) and the pymo Python library. The OF aimed to minimize the battery capacity based on the power balance between PV generation, load power, and battery power. The optimal capacity determined by the model was 15 Ah. The prototype utilizes a Lithium Ion (Li Ion-18650) arrangement of 6 cells in series. The Final Battery Capacity is 13.2 Ah for a Total Voltage of 22.2 V. The performance was evaluated through simulation, comparing the system with and without the integrated PV power source.

The work by (Hareesha N G) focuses on developing a solar-powered drone to increase flight endurance and reduce the carbon footprint of aerial operations. The drone design must consider factors like power requirements, high efficiency solar cells, surface area for integration, structural integrity, weight distribution, and aerodynamics. The proposed drone is a quadcopter. A 2200 mAh (2.2 Ah) capacity battery is used. The recommended motor is the A2212-1400KV BLDC Brushless Motor. With an All-Up Weight (AUW) of 1500 grams, the thrust requirement is 3000 grams (750 grams per motor in a quadcopter). The solar power generation system is integrated into the drone for energy harvesting. Four solar cells with a voltage output of 6V each are strategically positioned on the top surface. Two solar cells are connected in series in a row, and these rows are connected in parallel (or vice-versa in the flight- testing section, though the resulting parameters are the same). This configuration effectively doubles the voltage to 12V (aligning with the 11.1V Li-Po battery) and achieves a charging current of 1.6A. This 1.6A output comfortably surpasses the 1A minimum requirement to charge the battery effectively. The system exhibited a peak current production of 1.1A during optimal solar conditions, demonstrating its efficiency.

The paper by (Keerthana Reghunath) aims to demonstrate how solar cells can extend the range of an Unmanned Aerial Vehicle (UAV) and presents the history, applications, and a concise design estimate for a solar-powered UAV. The methodology focuses on comparing the range performance of a UAV using a battery-only configuration versus a battery-and-solar-cell combination. The process includes analyzing the power consumption of various components (motor, payload, etc.) to determine the total power required for flight and calculating the energy required for a given flight time. Designing the aircraft (sizing of wings, fuselage) to minimize drag and maximize efficiency. Estimating the increase in range achieved by supplementing the battery power with solar energy collection. The solar cells used to charge the battery during the day and supplement motor power. The battery provides power for the motor and avionics, especially during low sunlight or night flight. The key design goal is to determine the ideal battery capacity and weight that balances energy storage with reduced airframe weight. Carbon fibers are recommended for manufacturing components.

Figure 3. A Solar UAV [From (Keerthana Reghunath)].

Figure 3. A Solar UAV [From (Keerthana Reghunath)].

The paper by (Zhonghua Hu) addresses the urgent need for route planning in solar Unmanned Aerial Vehicles (UAVs), which are valued for their ultra-long endurance and "quasi-satellite" characteristics. Unlike conventional UAV route planning that focuses on threats like radar and missiles, solar UAV planning must also comprehensively consider factors affecting the solar cell's photoelectric conversion efficiency. The Ant Colony Optimization (ACO) algorithm is used to solve the combinatorial optimization problem of finding the lowest-cost route. The final design uses an enhanced version, the ES-TNF-ACO (Elite Strategy - Target Node Factor - Ant Colony Optimization) algorithm, which introduces a Target Node Factor to effectively guide the ants toward the destination node.

The paper by (S. Sathishkumar) introduces the concept of a solar-powered surveillance drone designed to overcome the short flight duration limitation of battery-powered UAVs. By integrating solar panels, the drone can extend its flight time and reduce the need for frequent charging. Selection of solar panels and integration with MPPT (Maximum Power Point Tracking) to optimize energy harvesting. Inclusion of components such as the drone frame, camera, flight controller, and batteries. The method aims to ensure efficient power management for propulsion and on-board electronics to enable longer flight endurance. The design of the solar drone includes Lightweight frame (carbon fiber/aluminum) to improve aerodynamics and support solar panel placement, High-efficiency solar panels mounted strategically to maximize sunlight exposure, Surveillance payload with HD/thermal cameras and communication systems for real-time data transmission, Flight controller with sensors (IMU, GPS, barometer) for stability, navigation, and power management, A hybrid solar + battery system for continuous power, supported by MPPT and DC-DC converters. The drone developed for surveillance is shown in Figure 4.

The paper by (Karthik Reddy Buchireddy Sri) considers the fundamental challenges for solar-powered aircraft, including: Geographical area of operation, Energy collection and storage mechanisms, Payload requirements and Overall design parameters. The draft of the design is being shown in Figure 5. A conceptual design for a plane with a total weight of 2 kg (including payload) is created and analyzed. The design is optimized in various aspects, from the airfoil selection to the complete structural design, to ensure better performance.

The study (O. A. Huseynov) focuses on the strategic operation of Solar-Powered Unmanned Aerial Vehicles (UAVs), particularly how to maximize their functionality by optimizing their flight trajectories with respect to atmospheric conditions. The core of the paper is a research study into the effectiveness and operational efficiency of UAVs equipped with solar panels, specifically when the aircraft is performing ascending and descending maneuvers. The key findings and methodologies include, Focus on Trajectory Optimization research is devoted to determining the optimal flight path (ascent and descent trajectories) for a solar-powered UAV to maximize the energy harvested by its solar panels and Atmospheric Impact Modeling is critical aspect of the study is the inclusion of atmospheric conditions in the energy calculation. The authors use a known formula which suggests that normal solar radiation is inversely dependent on the logarithm of PM2.5 (Particulate Matter 2.5) concentration. By considering this relationship between solar radiation and atmospheric opacity (PM2.5), the paper analyzed different flight trajectory options over a fixed time interval. This approach helps to identify how much higher or lower the UAV should fly to increase its energy intake, particularly in areas with significant atmospheric pollution.

A battery free UAV is attempted by (Jackson Liller Rishabh Goel), which is shown below in Figure 6. The UAV was built using commercial-off-the-shelf (COTS) components and innovative energy management systems to demonstrate sustainable, continuous aerial operation without batteries. Utilizes a solar harvesting system composed of an 86.4 W monocrystalline solar panel array, a supercapacitor bank (six 2.7 V, 500 F capacitors in series), and a maximum power point tracking (MPPT) circuit for energy regulation. The supercapacitor system replaces lithium-based batteries, providing fast charge/discharge cycles and extended operational life. Constructed from laser-cut vinyl-reinforced polystyrene with 3D-printed reinforcements, the fixed-wing design optimizes surface area for solar collection while maintaining high lift-to-drag ratio through MH117 airfoil geometry. The propulsion system consists of an Mn3110-17 Tiger motor paired with a 13x4.4 propeller, capable of generating up to 750 grams-force of thrust under ideal solar conditions. Introduces Greedy Energy-Aware Control (GEAC) and Predictive Energy-Aware Control (PEAC) algorithms to manage intermittent solar input. GEAC adjusts throttle based on predefined voltage thresholds (6–9 V) to prevent brownouts. PEAC dynamically estimates voltage changes over time to prevent total-loss-of-thrust events, offering smoother control during fluctuating sunlight conditions. The experimental findings include: Achieved top speed of 15 m/s and flight altitude of 3 meters, demonstrating controlled takeoff, flight, and landing. Solar data simulation (NSRDB) confirmed operational feasibility between 09:00–13:00 under average irradiance > 537 W/m². Viability maps indicated operability in most temperate and tropical regions between March–October. Proposed extensions include optimizing airframe aerodynamics to reduce parasitic drag and refining the power circuitry for continuous high-thrust operation. This research demonstrates the world’s first fully battery-free, solar-powered UAV, achieving autonomous flight powered entirely by sunlight.

(Mrs. M. Uma Mythraye) presents the design, fabrication, and testing of a solar-powered unmanned aerial vehicle (UAV) aimed at increasing flight duration and promoting sustainable aerial operations. The drone is built with key components including a frame, flight control board, BLDC motors (A2212–1400KV), Electronic Speed Controllers (ESC), Li-Po batteries of 2200 mAh, solar panels used is SunPower C-60 cells with 22% efficiency, Maximum Power Point Tracking (MPPT) unit, GPS module, transmitter, and receiver. The Proportional-Integral-Derivative controller (PID) controller ensures stability in pitch, roll, and altitude, while the MPPT circuit continuously optimizes solar power usage between the motors and the battery. Design calculations established that the power required for level flight is approximately 10.13 W with a cruise velocity of 7.56 m/s. The solar panels (0.04 m² area) with 15.6% efficiency and a performance ratio of 0.75 generate about 9.36 kWh of energy annually. The system uses 20 Li-Po batteries and two solar panels each producing 427.4 mAh, allowing a charging time of around 2.57 hours and an average flight endurance of 2.75 hours per full charge. Experimental results confirmed that the drone successfully harnesses solar power to operate its propulsion system and charge its onboard battery simultaneously. The flight tests demonstrated stable hovering, controlled navigation, and automatic return-to-home capability through GPS tracking. The integration of solar energy extended flight time compared to conventional battery-only drones, validating the feasibility of continuous, eco-friendly aerial operations.

The paper by (Jessa) presents a novel approach for developing a long-range data acquisition system using solar-powered unmanned aerial vehicles (UAVs) capable of operating in remote regions without electricity or communication infrastructure. The concept uses a chain of drones, where each UAV serves as both a data collection unit and a communication relay node, extending the total range far beyond that of a single drone. The main problems addressed are, sustainable energy harvesting for battery charging, selection of drone models that minimize mission time and cost and reduction of flight range due to payload weight. A total of 54 commercial UAVs and 25 solar cells were analyzed. Drone parameters such as battery capacity of 180–5700 mAh, voltage of 3.7V–22.8 V, flight time is for about 6–40 minutes, speed achieved if about 18–112 km/h, and range up to 52.7 km were evaluated. Solar panels were tested for power efficiency which gave the result of 0.42–1.64 W per 100 cm². The study calculated the Total Journey Time (TJT)—the time required to build a full drone network chain of 100 km, factoring in both flight and solar recharging cycles. The most efficient solar cell was identified as Cell ID 25 with 1.64 W/100 cm² efficiency. The Yuneec Mantis Q drone achieved the shortest total journey time (TJT) of 13.99 hours for a 100 km chain, with a battery capacity of 10.36 Wh, flight range of 39.6 km, and speed of 72 km/h. Hubsan X4 H107D and Overmax OV-X-Bee Drone 2.4 ranked second and third with TJTs of 19.79 hours and 23.03 hours, respectively. The least efficient drones were Syma X8 PRO (302.14 hours), Yuneec Typhoon Q500 (295.19 hours), and Yuneec Breeze (215.24 hours). When a 0.2 kg payload was added, flight ranges decreased significantly by 29% for Yuneec Mantis Q, 58% for Overmax OV-X-Bee Drone 2.4, and 85% for Hubsan X4 H107D, requiring more drones to maintain the same 100 km coverage. With payload, Yuneec Mantis Q still ranked best, with a TJT of 20.88 hours, while the Hubsan H501A and Overmax X-Bee Drone 8.0 followed with TJTs of 62.78 hours and 67.60 hours respectively.

The insightful work by (Joana Engana Carmo) paper presents a comprehensive study on enhancing the endurance of electric unmanned aerial vehicles (UAVs) by integrating photovoltaic (PV) solar panels into their structure. The research begins by addressing the major limitation of most UAV platforms which is restricted flight autonomy due to limited onboard energy storage and proposes solar augmentation as a potential solution. The authors conduct a detailed theoretical analysis of aerodynamic, thermal, and environmental interactions influencing PV performance on UAV surfaces, such as wind turbulence, irradiance variation, temperature dependence, and air pressure variation with altitude. Practical modeling shows that under optimal conditions such as in summer solstice at high altitude the solar panels can extend flight time by up to 7.5 minutes, representing nearly a 20% endurance improvement for a UAV with a 40-minute baseline, while under poor conditions like winter solstice and low irradiance the gain drops to mere seconds. Overall, the authors conclude that thin-film silicon PV panels can provide limited but measurable improvements in UAV endurance, especially under high-irradiance, low-weight conditions, and suggest flexible or solar-paint technologies as promising future solutions to overcome energy density and structural limitations.

(H. Hrauda) explore the structural and optoelectronic integration of micro-textured silicon photovoltaic cells into carbon-composite UAV wings for enhanced energy harvesting. The team developed a fabrication method embedding thin PV cells whose size is less than 100 µm within the wing’s composite laminate using resin-transfer molding, forming a multifunctional structure that combines both load-bearing and energy-generating capabilities. Finite element analysis verified minimal structural weakening (less than 3% strain reduction), while optical simulations predicted up to 28% increased power output due to enhanced photon capture. Experimental outdoor testing on small-scale UAV prototypes confirmed a 17% range extension compared to non-solar counterparts.

2.2. Solar Power Integrated Micro UAVs

(Farid Ibrahim) focuses on evaluating the feasibility of integrating solar photovoltaic (PV) panels with micro fixed-wing UAVs for real-time in-flight battery recharging. The study involves designing and testing a solar-assisted propulsion system that uses lightweight monocrystalline panels mounted on the UAV’s wings to continuously supplement battery power during flight. The authors developed a power management system to regulate charging and discharging cycles between the panels and lithium-polymer batteries. Experimental flight trials under full sunlight demonstrated that solar charging extended endurance by approximately 22–30%, depending on irradiance levels. The research also analyzes the trade-offs of additional structural mass and drag caused by solar integration. Computational analysis showed only minor aerodynamic penalties when the panels were flush-mounted.

The paper by (Aly Abidali) details the design, development, and testing of the Micro Solarcopter, a solar-rechargeable multirotor micro aerial vehicle (MAV) aimed at extending drone endurance using solar energy. The Micro Solarcopter measures 0.15 m × 0.15 m × 0.02 m, weighs 0.071 kg, and is designed for energy autonomy through integrated solar charging. The research addresses the problem of short flight time and high energy demand in rotary-wing drones, which limits their operation compared to fixed-wing systems. The proposed solution combines high-efficiency SunPower C60 solar cells (which have 22% efficiency) with a lightweight lithium-polymer (Li-Po) battery and an intelligent power management system that enables automatic hibernation and solar recharging. The MAV’s key components include a 3D-printed PLA frame, coreless micro motors with gearboxes, a Turnigy Nano-Tech 0.3 Ah, 45–90 C Li-Po battery, and a custom four-cell solar panel (1.65 W output). Control and monitoring are achieved using a HappyModel F3 Evo flight controller, ATtiny85 microcontroller, and Pololu voltage regulators, with an onboard FPV camera providing live video transmission. The experiments showed that purely solar-powered flight without energy storage is not feasible at MAV scale due to surface area and power conversion limitations. However, solar-rechargeable flight significantly enhances operational autonomy.

The Micro Solarcopter demonstrates the first functional solar-rechargeable multirotor MAV, capable of flight, autonomous energy management, and environmental sustainability. The study concludes that future work should focus on fully autonomous flight, swarm coordination, and real-world applications such as surveillance, environmental monitoring, and planetary exploration.

2.3. Solar Power Integrated Mini UAV

The paper by (Philipp Oettershagen) presents the complete design, analysis, and experimental validation of AtlantikSolar, a small, hand-launchable solar-powered unmanned aerial vehicle (UAV) capable of achieving true multi-day flight. The study focuses on developing a comprehensive Conceptual Design and Analysis Framework (CDAF) that models the UAV’s full energy cycle i.e. from solar power generation to battery storage and propulsion consumption across both day and night conditions. The AtlantikSolar UAV is a lightweight 6.93 kg platform with a 5.69 m wingspan, covered by 88 high-efficiency SunPower solar cells (which has 23.7% efficiency) producing a peak of 275 W under ideal conditions. Its lithium-ion battery pack (2.92 kg, 733 Wh) is integrated into the wing spar to maintain structural integrity and center of gravity balance. The power system includes custom-designed maximum power point tracking (MPPT) electronics and a battery management system for optimal energy flow. The aircraft’s avionics are centered on a low-power PX4 autopilot equipped with GPS, IMU, airspeed sensors, and an extended Kalman filter for precise long-term autonomous navigation. The aerodynamic design, lightweight structure, and intelligent energy management collectively enable long endurance with a high degree of reliability. The UAV’s performance was validated through a record-breaking 81-hour continuous flight, covering approximately 2338 km over four days and three nights, setting a new world endurance record for aircraft below 50 kg.

2.4. Organic/Thin Film Polymer Solar Fuel Cells

A comprehensive review by (Krzysztof Sornek)examines the technological state-of-the-art and developmental directions of solar-powered UAVs (SUAVs), encompassing structural design, materials, energy storage, propulsion, and operational strategies. Solar UAVs are characterized by lightweight, high-aspect-ratio fixed-wing configurations that maximize solar surface area and aerodynamic efficiency. The review outlines UAV classifications based on geometry, range, and propulsion type, emphasizing the advantages of electric solar systems using BLDC motors with integrated energy management systems (EMS). The electric propulsion layout includes photovoltaic modules, a DC bus, inverters, and a Battery Management System (BMS) that regulates energy flow between generation, storage, and thrust. Structural optimization is central, materials such as carbon fiber and composite laminates are preferred for their high strength-to-weight ratios, while additive manufacturing techniques (like continuous-belt 3D printing) are highlighted for producing seamless aerodynamic components. Aerodynamic analyses show that distributing PV cells along high aspect-ratio wings can enhance lift-to-drag ratios when properly integrated flush with the surface. Key technological challenges include mitigating structural deformation, maintaining laminar flow, and balancing added PV mass against payload and endurance. The paper reviews optimization algorithms especially genetic algorithms for minimizing mass and maximizing energy efficiency. Examples like “Newsolar” and “SolarÍO” UAVs demonstrate improved energy harvesting and endurance through smart configuration. Future prospects include the development of flexible solar modules, hybrid battery-fuel systems, advanced MPPT algorithms, and multi-objective design frameworks coupling aerodynamics and power management. Overall, the review consolidates engineering principles and research trajectories toward fully sustainable and autonomous solar-powered flight systems.

This study by (H. Hrauda) presents a novel structural integration of micro-textured photovoltaic (PV) cells directly into an ultra-light composite UAV wing, designed to extend flight range without significant weight penalties. Traditional UAVs that mount solar panels externally suffer from silica wafer cracking, aerodynamic inefficiencies, and excessive mass from adhesives and resin layers. To counter these limitations, the researchers engineered a carbon-fiber-based sandwich wing structure using aerogel cores to achieve significant weight reduction (reducing the wing mass from 850 g to 550 g). The PV cells, fabricated from 3-inch p-type silicon wafers (350 µm thick, resistivity 1–3 Ω·cm), were dimensioned at 10 × 22 mm² and embedded within the wing structure using optically stable epoxy resin. Mechanical deformation analyses and simulations using beam-deflection theory confirmed the cells’ tolerance to in-flight loads, with maximum deflection below 0.6 mm. Surface texturing through photolithographically- defined inverse pyramids (10 µm) quadrupled light absorption efficiency by reducing reflection losses and improving infrared absorption. Testing confirmed mechanical durability under UV and thermal cycling. The prototype flight tests demonstrated that integrating these PV cells resulted in a 33% increase in UAV endurance using only one modified wing. This approach marks a major step toward structurally integrated photovoltaic UAV systems combining lightweight composite aerostructures with micro-fabricated solar technologies.

(Matias Alegre Maurer) investigate the feasibility of integrating perovskite solar cells into autonomous drones for extended missions in remote or energy-scarce environments such as jungles, oceans, high-altitude regions, and extraterrestrial terrains. The study highlights perovskite materials superior power-to-weight ratio (approximately 44 W/g), flexibility, and increasing efficiency (exceeding 29%) compared to traditional silicon cells. A prototype 3D-printed drone was modified to include thin-film halide perovskite cells, evaluating their effect on energy capture, mass, and operational duration. The results demonstrate significant potential for perovskite integration in lightweight UAV frames due to their minimal thickness which is one-twentieth the width of a human hair and resilience in harsh environments, with studies noting increased efficiency after prolonged exposure to space conditions. The research details drone use cases across terrains such as LiDAR equipped drones for rainforest mapping, solar-powered ocean drones for marine monitoring, high-altitude pseudo-satellite UAVs (e.g., Zephyr) for stratospheric missions, and conceptual extraplanetary flyers like NASA’s Ingenuity and Dragonfly. The study also reviews concurrent advancements in solid-state and lithium-sulfur batteries, graphene-based lightweight frames, parylene nano- coatings, and intelligent energy management algorithms. Collectively, these innovations could allow future drones to autonomously recharge in situ using integrated perovskite photovoltaics, eliminating the need for docking. The paper concludes that continued material stabilization and flexible encapsulation research are essential for scalable, long-term deployment of perovskite-based solar drones in both terrestrial and extraterrestrial exploration.

This paper by (Bekele Hailegnaw) presents a major advancement in ultralight photovoltaic technology for flight applications. The research, led by Johannes Kepler University Linz, introduces flexible quasi-two-dimensional (quasi-2D) lead halide perovskite solar cells fabricated on ultrathin (less than 2.5 μm) polymer substrates coated with an aluminum oxide barrier layer that enhances environmental and mechanical durability. By incorporating alpha-methylbenzyl ammonium (MBA) iodide into the perovskite crystal structure, the cells achieve reduced non-radiative recombination and enhanced phase stability under mechanical stress. The team achieved a record specific power of 44 W g⁻¹ (average 41 W g⁻¹) with a peak power conversion efficiency of 20.1% and an open-circuit voltage of 1.15 V, without using transparent conductive oxides. These devices were scaled into modules comprising 24 interconnected 1 cm² cells that collectively covered 24 cm² and represented just 1/400th of a drone’s mass. The module successfully powered a 13 g quadcopter, enabling fully energy-autonomous flight that exceeded normal battery endurance limits. The perovskite modules retained up to 90% and 74% of their initial efficiencies after 50 hours of continuous testing under ambient conditions, demonstrating strong operational robustness. This work validates quasi-2D perovskite photovoltaics as high-performance, lightweight, and cost-effective candidates for powering autonomous drones and other mobile robotics, highlighting their potential for aerospace and terrestrial energy harvesting applications in ultra-light flexible electronics.

1.1. Methodology of Integrating Solar Power with UAVs

Unmanned aerial vehicles are diverse in their utility, build and cost. They are almost employed in every service sector such as mapping and geographical surveillance, goods delivery, photography and videography, aerial monitoring and surveillance, agricultural monitoring and pesticidal purposes and the budding concept of air taxis. With UAVs emerging at the forefront of aviation, integrating sustainability and experimenting with the same in impeccable. With the literature presented here, significant points of consideration with respect to the design of the UAV while integrating solar panels, are quoted here, eventually paving a way for a comprehensive framework for the design of SPUAVs.

3.1.1. Engineering Design of the UAV with High Endurance

Any aerial vehicle is highly dependent on the interlinked concepts of aerodynamics, weight distribution and the center of gravity with the constraint of structural integrity. This determines the feasibility of the vehicle and eventually accounts for the performance parameters of range and endurance. A constraint analysis graph, generated using MATLAB code, was used to evaluate performance based on power-to-weight or thrust-to-weight ratios and wing loading by (Tomar). The fuselage design for solar aircraft is simplified by the absence of fuel tanks and fuel lines. A single fuselage and tail boom was deemed most suitable for a lightweight and efficient structure, minimizing surface friction drag and simplifying construction. The length of the fuselage was curtailed to decrease weight and drag. The designed UAV can demonstrate maneuvers at 5000 meters and demonstrates exceptional flight control and stability with a stalling angle of degrees. Upon the factor of weight addition due to the solar modules, most researchers had opted for a viable solution of Li- Po batteries as done by (Asutosh Pati) who had reported that the centre of gravity of the wing is maintained at the optimum quarter chord and a low dihedral is maintained, upon the right component placements including Li- Po batteries. For the structural integrity, lightweight carbon fibres are quoted by researchers. Carbon fibers are recommended for manufacturing components due to their lightweight and strong properties as mentioned by (Keerthana Reghunath). The design involves integrating the solar panels directly onto the wings. Moreover (S. Sathishkumar) quoted that this alternative supports for improved aerodynamics and better solar panel placement.

As mentioned before, the aid of CFD for a multi case analysis is undeniable. Using computational fluid dynamics based on the Navier–Stokes equations and a RANS (Reynolds - Averaged Navier – Strokes Equation) turbulence model, (Joana Engana Carmo) had simulated the aerodynamic flow and pressure distribution on the UAV structure to ensure that the thin-film crystalline silicon solar cells can withstand mechanical stresses during flight. The simulation results confirm that the aerodynamic pressures do not exceed the material yield limits, validating the structural feasibility of solar panel integration. Subsequent solar performance simulations, incorporating irradiance, wind cooling, and temperature effects through the Skoplaki 2 model, demonstrate that power generation and efficiency depend heavily on orientation, altitude, and time of year.

Finite element analysis verified minimal structural weakening (less than 3% strain reduction), while optical simulations predicted up to 28% increased power output due to enhanced photon capture. Experimental outdoor testing on small-scale UAV prototypes confirmed a 17% range extension compared to non-solar counterparts. (H Hrauda)

Focusing the core issue of limited battery life for surveillance drones, under desirable environmental conditions, the incorporation of solar power had drastically reduced the sue of the battery capacity stored by 22.5% as reported by (Vivek Sharma). Similarly, (Hareesha N G) reports a current production of 1.1 Amperes in optimal solar conditions, from the SPUAV they had developed. (Karthik Reddy Buchireddy Sri) had quoted that geographical area of operation, energy collection and storage mechanisms, payload requirements and overall design parameters are the significant aspects for the design of an SPUAV.

(O. A. Huseynov) had focused on Trajectory Optimization research to determine the optimal flight path (ascent and descent trajectories) for a solar-powered UAV to maximize the energy harvested by its solar panels and Atmospheric Impact Modeling is critical aspect of the study is the inclusion of atmospheric conditions in the energy calculation.

3.1.2. Energy Optimization

As opposed to any experiments or practical modelling of a design at its proposition, researchers choose to simulate and computationally analyze the parameters. Furthermore, a single engineering model in itself is seldom self- efficient nor advantageous unless there are kits and components installed to monitor the functioning, health and operability of various components, in major cases. (Dr. Raghvendra Tiwari) had employed a Maximum Power Point tracking (MPPT) kit to maintain the voltage level and ensure the power delivery to be maximum from the solar cells to the battery and eventually the circuits. (S. Sathishkumar) also employs MPPT for optimal energy utilization. In order to compute the effects of solar radiation under various meteorological conditions, (Zhonghua Hu) had developed multiple mathematical models along with the optimization algorithms to predict the performance of the solar cells, considering the factors of solar irradiation angle, mountain shadow occlusion, cloud shading. In addition to this, they had also developed a mountain shadow occlusion cost calculator based on the geometric relationship between the UAVs position, the mountain’s height and the sun’s altitude angle. From the work carried out by (Jessa) a total of 54 commercial UAVs and 25 solar cells were analyzed for a solar drone with the parameters of battery capacity of 6- 40 minutes, velocity of 18- 112 kmph and a maximum range of 52.7 km. The resulting power efficiency lies in between the range of 0.42- 1.64 Watts per 100 sq.cm. Upon calculating the total journey time (TJT), which is the time required to build a drone network chain of 100 km, factoring in both flight and solar recharging cycles. From this the most efficient solar cell was identified as Cell ID 25 with 1.64 Watts per 100 sq.cm efficiency, which also proved to be economical. (Farid Ibrahim) had developed a and lithium-polymer batteries. Experimental flight trials under full sunlight demonstrated that solar charging extended endurance by approximately 22–30%, depending on irradiance levels. The research also analyzes the trade-offs of additional structural mass and drag caused by solar integration. Computational analysis showed only minor aerodynamic penalties when the panels were flush-mounted. In the UAV developed by (Philipp Oettershagen) the UAV had demonstrated exceptional energy resilience, the minimum state-of-charge (SoC) of the battery never dropped below 40%, even during the longest night. On average, the system had 6.8 hours of excess endurance and 6.2 hours of daylight charge margin, indicating significant energy surplus for unforeseen weather conditions or additional payload power needs. Even under partial cloud cover and turbulent winds up to 17 m/s, the UAV maintained stable flight, validating both the robustness of the CDAF design approach and the system’s overall efficiency. (Franklin Salazar) had also developed a low flight UAV catering to the unique meteorological conditions of Ambato, Ecuador and had attained an appreciable increase in endurance as opposed to the weight addition of 690 grams due to the solar modules.

Moreover, a vast number of researchers had reported the use of Li- Po batteries for an efficient charging time as opposed to it weight penalty as mentioned by (Mrs. M. Uma Mythraye)

There are also novel approaches for energy conservation as introduced by (Jackson Liller Rishabh Goel) on employing a supercapacitor bank. a supercapacitor bank (six 2.7 V, 500 F capacitors in series), and a maximum power point tracking (MPPT) circuit for energy regulation. The supercapacitor system replaces lithium-based batteries, providing fast charge/discharge cycles and extended operational life. Constructed from laser-cut vinyl-reinforced polystyrene with 3D-printed reinforcements, the fixed-wing design optimizes surface area for solar collection while maintaining high lift-to-drag ratio through MH117 airfoil geometry. Power tests under simulated solar irradiance showed continuous thrust production up to 350 grams-force, Supercapacitors charged to 12 V in 150 seconds under peak irradiance (40 W), providing robust power buffering against solar intermittency. Proposed extensions include optimizing airframe aerodynamics to reduce parasitic drag and refining the power circuitry for continuous high-thrust operation. The combination of supercapacitor energy storage and adaptive control algorithms establishes a basis for future UAVs capable of indefinite flight under adequate solar conditions.

3.1.3. Note on the Global Trend Towards Sustainability

The main focus is to comprehend the contemporary techniques used for market rebalancing, pricing, and managing the supply demand balance in a power grid with increasing renewable penetration in the work by (J. Shri Saranyaa). The paper notes that power generation globally is rapidly transitioning to renewable energy technologies to address the energy crisis and promote clean energy. This transition is accelerating due to the signing of the Paris Agreement and the goal of achieving grid parity, where RES can compete economically with conventional energy generation. The overall global renewable energy capacity has seen incredible growth. Levelized Cost of Energy (LCOE) is presented as the primary global evaluator for energy pricing, ensuring a fair valuation of generation costs and tracking the achievement of grid parity for different technologies. The survey extensively reviews recent methodologies for LCOE estimation.

Upon considering all these nuances, we present a summarizing framework that serves as an overview for SPUAV design: