Impacts of voltage bias on halide perovskite devices
Abstract
We propose to understand issues regarding bias instability of perovskite solar cells. Current perovskite device optimization only co nsiders positive bias up to open-circuit voltage, and stability measurements are typically performed at maximum power point. In othe r words, disregarding reverse bias. If perovskite solar cells are to become a commercially viable technology, effort must be made to consider their operation in the fundamental building block of any thin film photovoltaic system, and this is the monolithic module. When such a module is partially shaded, the photocurrent from the illuminated cells are forced through the off cells which are in the shade. This thrusts them quite considerably into reverse bias, where conductivity is low and thus heating and, perhaps more imp ortantly, electrochemical reactions, become problematic. In crystalline and amorphous silicon as well as CIGS modules, bypass diodes are integrated to protect cells against the damage wrought by partial shading, typically every 10-20 cells. This implies that, in w orst case, these modules are designed to withstand at least 10 V of reverse bias. To make perovskite modules cost competitive, it wo uld be ideal to adopt a similar bypass diode frequency, as the prospect of a bypass diode for each cell in the module would raise mo dule costs considerably.This proposal seeks to uncover the fundamentals of interfacial electrochemical interactions involving metal halide perovskite semiconductors. to establish a basis for evaluating the electrochemical stability of perovskite layers and interfa ces, and stabilizing against reverse bias that results from module partial shading. This work is necessary in order to allow perovsk ite semiconductors to be stable and operate in the field for years something that is currently far out of reach. There is thus an urgent need to develop methods to identify the myriad electrochemical and photoelectrochemical reactions that can occur at these int erfaces, and engagein efforts to make informed decisions to try to obviate these processes. Interface layers need to be stable again st both anodic and cathodic reactions, regardless of whether hole or electron injecting/collecting.Our primary research objectives a re to (1) identify anodic and cathodic reactions at perovskite interfaces with metal oxides and organic transport layers, and (2) id entify accurate voltage thresholds for these reactions. Our proposed work is ideally positioned to contribute to the stability gains needed to make perovskite photovoltaic modules viable as a low-cost, lightweight power generating system.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 20, 2021
- Source ID
- N000142112767
Entities
People
- Barry P Rand
Organizations
- Office of Naval Research
- Trustees of Princeton University
- United States Navy