Gene

Engineering

Chemical physics

Materials science

Protonation

Biochemistry

Perovskite (structure)

Transfection

Silicon

Chemical engineering

Polyethylenimine

Polymer

Tandem

Nanotechnology

Organic chemistry

Composite material

Crystallography

Chemistry

Energy conversion efficiency

Optoelectronics

Joule

<h2>Summary</h2> The present p-i-n perovskite solar cells are less efficient than their n-i-p counterparts, fundamentally limited by deep-level traps of minority carriers at surfaces. Here, we explore perovskite/polymer multi-mode interactions by comparing the amine group's various configurations and protonation states in the polyethylenimine (PEI) family. We correlate these interactions with specific deep-trap states by combining deep-level transient spectroscopy (DLTS) and density functional theory (DFT). We identify an <i>in-situ</i> protonation process that significantly reduces deep-level traps of minority carriers. The conventional <i>ex-situ</i> protonated and non-protonated groups do not exhibit this effect. For 1.55-eV p-i-n device, we achieve a high power conversion efficiency (PCE) of 24.3%. For 1.65-eV p-i-n devices directly applicable for tandem on silicon bottom cells, the PCE is improved from 19.4% to 22.3%. The cells exhibit no degradation in accelerated aging testing at 85°C for >1,000 h and maximum-power-point (MPP) tracking for >1,000 h.

Correlating the perovskite/polymer multi-mode reactions with deep-level traps in perovskite solar cells