Researchers unveil multi-mode reactions in perovskite solar cells

• As an appealing photovoltaic or pv material, metal halide perovskite yields high efficiency in solar cells. Nonetheless, the deep-level traps of minority service providers at the surface of the p-i-n perovskite solar cells can reduce nonradiative recombination. The accurate passivation of deep-level traps has actually been a major emphasis in increasing the power conversion efficiency (PCE) to the theoretical Shockley-Queisser restriction.

Just recently, a study team led by Prof. Xu Jixian and Prof. Wu Xiaojun from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), as well as their collaborators from Suzhou Institute of Nano-Tech and also Nano-Bionics of CAS disclosed the perovskite/polymer multi-mode communications as well as their correlation with the passivation of the deep-level traps, and also uncovered a new in-situ protonation procedure that substantially minimizes the deep-level traps of minority carriers. This work was published in Joule.

Previously recognized interaction modes at the perovskite/polyethyleneimine (PEI) user interface consist of standard physisorption and also metal-chelation, which either reveals small passivation effects or often tends to passivate the majority service provider traps. To conquer these issues, the scientists used high-sensitivity X-ray photoelectron spectroscopy (XPS) and sum-frequency-generation spectroscopy to recognize in-situ protonation process of the amine team at the perovskite/PEI surface area.

They studied the correlations in between different interaction modes and also traps by incorporating deep-level transient spectroscopy (DLTS) and also thickness functional theory (DFT). The results showed that the in-situ protonation can successfully passivate deep-level traps of minority carriers in perovskite, while standard ex-situ protonation can't.

The scientists also contrasted the passivation effect and also the volt-ampere features of PEI with different setups such as straight, branched and ethoxylated PEIs, and also exposed the synergistic effect of the practical group and also arrangements. They recommended that besides the routine thinking about improving the applicability of passivation by raising the kinds of functional teams, the multi-mode passivation of a solitary useful group must also be considered.

In addition, the scientists utilized the passivation technique in p-i-n perovskite solar cells of various band voids, all of which revealed significant improvement in PCE.

The perovskite/polymer multi-mode communications disclosed in this work give a feasible means for creating an universal passivation strategy and also improving power conversion efficiency in the future.