Effect of annealing on performance of PEDOT：PSS/n-GaN Schottky solar cells

We develop a heterojunction-based Schottky solar cell consisting of n-type GaN and PEDOT:PSS and also investigate the effect of annealing on the performance of the solar cell. The results show that the open circuit voltage (V_oc) increases from 0.54 V to 0.56 V, 0.71 V and 0.82 eV while decreases to 0.69 eV after annealing at 100 ℃, 130 ℃, 160 ℃, and 200 ℃, respectively, which can be ascribed to the change of barrier height of PEDOT:PSS/GaN Schottky contact induced by variation of the work function of the PEDOT:PSS. Furthermore, the conductivity and surface roughness measurements of the PEDOT:PSS indicate that annealing can increase the grain size and improve the connectivity between PEDOT and PSS particles, and cause thermal degradation at the same time, which leads to the rise in short-circuit current density (I_sc) up to 160 ℃ and the dropoff in I_sc after annealing at 200 ℃.