LAUSR

Recently, various lanthanide ions (Ln3+) have been successfully doped into perovskite quantum dots (PQDs) and quantum-cutting emission of 2F5/2-2F7/2 for Yb3+ with measurable inner efficiency more than 100 % has been discovered, applied as the luminescent converter of solar cells, which has opened a new branch for the application of PQDs. In this work, to further improve the quantum-cutting efficiency of Yb3+, the co-doping and tri-doping methods were displayed to improve the quantum cutting emission of PQDs. The Yb3+-Ln3+ (Ln=Nd, Dy, Tb, Pr, Ce) pairs doped CsPbClxBryI3-x-y PQDs were fabricated, which all displayed excitonic emissions, narrow-band emission of Ln3+ ions and quantum cutting emission of Yb3+ ions. It was interesting to observe that Yb3+-Pr3+ as well as Yb3+-Ce3+ pairs could effectively sensitize the emission of Yb3+, owing to Pr3+ and Ce3+ ions offered intermediate energy states close to the exciton transition energy of the PQDs. After host composition optimization and tri-doping investigation, overall emissions with 173% photoluminescence quantum yield (PLQY) were obtained in the Yb3+-Pr3+-Ce3+ tri-doped CsPbClBr2 PQDs. Then, the tri-doped PQDs was designed as the down-converter for the CuIn1-xGaxSe2(CIGS) as well as the silicon solar cells, which relatively leads to enhancement of power conversion efficiency (PCE) as high as ～20%. The modified CIGS was further employed to charging the smart mobile phone, which could largely shorten the charging time from 180 to 150 min. This finding is of great significant for expanding the application fields of the impurity doped PQDs.