Analyzing the operational versatility of advanced IBC solar cells at different temperatures and also with variation in minority carrier lifetimes

Abstract

In this work, doped and dopant-free carrier-selective passivating contacts have been incorporated in Interdigitated Back Contact solar cells. TCAD simulation study was done to check the performance of an IBC-SHJ (Silicon Hetero-Junction) and IBC-POLO (POLy-silicon on Oxide as seen in TOPCon) cell structures for both p and n-type wafers. The IBC-POLO structure was also repeated with HfO₂ and ZrO₂ over electron transport and hole transport layers, respectively. Simulation study was done by replacing the doped silicon layers with dopant-free Transition Metal Oxides (TMOs). NiO was used as a dopant-free hole-selective contact, whereas Nb₂O₅ was used a dopant-free electron-selective contact. The fabrication of these materials is non-hazardous and at low temperatures due to which they are preferable over the doped Si layers that require toxic gases like phosphine, diborane, etc. and may also require high temperatures. For example, poly-Si layer applied in IBC-POLO requires an annealing temperature of over 800 °C; similarly, the diffusion of Front Surface Field (FSF) layer in normal IBC cells also requires the same high temperature. Temperature variation was done on these structures to check the dependence of solar PV parameters of each IBC structure on different temperatures. Same variation was checked with minority carrier lifetime of the silicon wafer.