Enhanced carrier diffusion makes back-contact perovskite solar cells more efficient

Exciton Science researchers based at Monash University have demonstrated a mechanism for reducing parasitic light absorption and improving the efficiency of perovskite solar cells (PSCs) with back-contact architecture.

In work led by PhD student Boya Zhao and supervised by Professor Udo Bach, the researchers found that perovskite thin films with a preferred out-of-plane orientation show improved carrier dynamic properties.

With the addition of guanidine thiocyanate, the films exhibit carrier lifetimes and mobilities increased by three to five times, leading to diffusion lengths exceeding 7 mm.

The enhanced carrier diffusion results from substantial suppression of nonradiative recombination and improves charge collection.

Devices using such films achieve reproducible efficiencies reaching 11.2%, among the best performances for back-contact PSCs.

The findings demonstrate the impact of carrier dynamics on back-contact PSCs and provide the basis for a new route to high-performance back-contact perovskite optoelectronic devices at low cost.

The results have been published in Angewandte Chemie and are available here.