Efficient chromium ion passivated CsPbCl3:Mn perovskite quantum dots for photon energy conversion in perovskite solar cells

Expanding the spectrum response through photon energy conversion is an effective way to further increase the power conversion efficiency (PCE) of perovskite solar cells (PSCs). In this work, the Cr(3+)passivated CsPbCl3:Mn(2+)perovskite quantum dots (PQDs) were synthesized, which display high absorption of ultraviolet (UV) light, improved photoluminescence (PL) with a large Stokes shift, and improved stability, which is the ideal photon energy converter for PSCs. The optimal photoluminescence quantum yields (PLQYs) of CsPbCl3:Cr3+,Mn(2+)PQDs reach 97% with 7.5 mol% of Cr3+. The enhancement of PLQYs can be attributed to the passivation effect of Cr(3+)and the increased energy transfer rate from perovskite to Mn2+. The efficient converter was assembled on the surface of the PSCs, which display 7.40% relative increase of PCE from 20.81% to 22.35%. This work provides a method to tune the PL properties of quantum dot materials and a universal strategy to further increase the performance and even break the Shockley-Queisser limit of solar cells.