China’s dual-faced solar cells hit 23.4% efficiency record, cut power loss dramatically

Researchers in China have developed an innovative approach to significantly improve bifacial perovskite solar cells (Bi-PSCs), achieving a record power conversion efficiency (PCE) of 23.4% while dramatically reducing photon loss—a key factor limiting these cells’ performance. By identifying photon loss as the primary cause of performance degradation, the team introduced a high-quality thick-film deposition method that regulates perovskite crystallization dynamics. This method employs a multifunctional additive, 1-ethyl-3-guanidinium thiourea hydrochloride (EGTHCl), to control nucleation and crystallization in highly concentrated precursor solutions, resulting in dense, uniform, and defect-free perovskite films. The enhanced Bi-PSCs not only reached a record efficiency but also demonstrated remarkable stability, retaining over 80% of their initial performance after more than 2,000 hours of continuous light exposure. This advancement addresses the inherent design challenge of bifacial cells, which use semi-transparent rear