Temperature-dependent photovoltaic properties of 54-μm-thick InGaP/InGaAs/Ge triple-junction solar cell on flexible substrate

Abstract

The power conversion efficiency (PCE) of a 54-μm-thick InGaP/InGaAs/Ge triple-junction (3-J) solar cell transferred on a flexible polyimide (PI) substrate (transferred thinned solar cell) was investigated at −150 °C–+150 °C under the AM0 condition. The transferred thinned InGaP/InGaAs/Ge 3-J solar cell was fabricated by grinding and polishing a 190-μm-thick commercial InGaP/InGaAs/Ge 3-J solar cell (pristine thick solar cell). The temperature coefficients for Voc, Jsc, PCE, and Pmax in the pristine thick solar cell were −4.95 mV/°C, 11.75 μA/cm2/°C, −0.04%/°C, and −16.56 μW/°C, respectively, in the temperature range of −150 °C to +150 °C. In the transferred thinned solar cell, the temperature coefficients for Voc, Jsc, PCE, and Pmax were −0.97 mV/°C, 2.53 μA/cm2/°C, −0.01%/°C, and −2.16 μW/°C in the temperature range of −150 °C to 0 °C. In the temperature range of 0 °C–150 °C for the transferred thinned solar cell, the temperature coefficients for Voc, Jsc, PCE, and Pmax were −4.53 mV/°C, 9.22 μA/cm2/°C, −0.04%/°C, and −16.81 μW/°C, respectively. The temperature-dependent external quantum efficiency (EQE) of each subcell in a pristine thick and transferred thinned solar cell explained the result that the absolute values of the temperature coefficients in the transferred thinned solar cell are lower than those in the pristine thick solar cell in the −150 °C–0 °C temperature range. A structural deformation was observed in the transferred thinned solar cell and it affected the temperature-dependent photovoltaic properties of the transferred thinned solar cell. The deformation also changed the photovoltaic properties of the transferred thinned solar cell measured under vacuum pressures for a high-altitude environmental simulation.