The (Al,Ga)N nanowire film with good flexibility and transparency has been achieved by a electrochemical procedure with low cost. Detaching such films can enhance the peak responsivity and decrease the decay time of ultraviolet photodetectors.

A simple method is proposed for manufacturing the flexible III–V inverted metamorphic solar cells by low‐temperature transfer technology. Benefiting from the special low‐temperature adhesive and the Cu‐plated thin films, only one‐time bonding and extremely easy debonding are needed through the whole process and a negligible effect of residual stress can be obtained, which is critical to large‐size device fabrication. The optical model of light trapping and photon recycling based on the native textured back‐surface reflector of the flexible solar cell is constructed to design the antireflection coating. The flexible 4 in solar cells with a weight‐area density of only 169 g m−2 are successfully mass‐produced. The analysis of the individual subcells using optoelectronic reciprocity relation indicates that the GaAs middle subcell should be further optimized to improve the performance. The technique can be expected to achieve mass production of flexible high‐efficiency large‐size solar cells with low cost.

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Inverted metamorphic solar cells play an important role in the field of photovoltaics, because it can directly grow stacked tandem junctions with different bandgaps according to the spectrum. We have found that the four‐junction AlGaInP/AlGaAs/InGaAs/InGaAs solar cells with the bandgap of 1.96/1.55/1.17/0.83 eV on the basis of the inverted metamorphic three‐junction AlGaInP/AlGaAs/InGaAs materials will cause a serious decrease in short‐circuit current density but with a normal open‐circuit voltage. The sharp decrease in short‐circuit current density is not attributed to the mismatched buffers dislocations penetrating into the active region of the InGaAs subcells but resulted from the minority carrier recombination due to defects in the AlGaInP subcell, which is observed directly from transmission electron microscopy, external quantum efficiency, electroluminescence, and secondary ion mass spectrometry measurements. The process of growing AlGaInP materials by metal–organic chemical vapor deposition easily introduces Al‐O deep‐level defects, resulting in the poor collection of minority carriers in AlGaInP materials. After improving the growth conditions of AlGaInP materials, a four‐junction solar cell with a photoelectric conversion efficiency of 34.9% and an open‐circuit voltage of 3.53 V was obtained.

A thin‐film AlGaInP/AlGaAs/InGaAs/InGaAs inverted metamorphic multijunction solar cell with a bandgap of 1.96/1.53/1.16/0.83 eV is fabricated. The photoelectric conversion efficiency reaches 34.89% with an open‐circuit voltage of 3.54 V under AM1.5 G spectrum. The analysis of individual subcells is the key to evaluating the performance of multijunction solar cells. The current density versus voltage characteristics of four subcells are calculated using optoelectronic reciprocity relation between the external quantum efficiency and the different injection current densities electroluminescence. The analysis of the performance characteristics of four subcells concludes that the key to limiting the overall efficiency improvement is the deep‐level recombination of the AlGaInP top subcell and the bulk recombination of 0.83 eV InGaAs bottom subcell. Targeted optimization of the top subcell and the bottom subcell is expected to significantly improve efficiency.

Lightweight and flexible III–V solar cells create new opportunities for application in satellites, drones, and wearable devices. In this article, a module manufacturing scheme based on resistance welding and lamination technology is proposed to meet the demands of practical application. A combined laminate structure of ethylene–tetrafluoroethylene plus ethylene octene copolymer and polyimide is used to encapsulate flexible III–V solar cells. In laboratory measurements with a spectrum close to AM1.5G, the photoelectric conversion efficiency of the flexible solar cell is 34.4% with an open‐circuit voltage of 3.04 V, and the efficiency of the flexible module is 32.7% with a weight density of 469 g m−2. The electroluminescence measurements show good performance of the flexible solar cell module, which is expected to achieve large‐size flexible III–V solar cells encapsulation.