Switchable photovoltaic windows enabled by reversible photothermal complex dissociation from methylammonium lead iodide

Lance M Wheeler,Nathan R Neale,David T Moore,Robert C Tenent,Noah J Stanton,Elisa M Miller,Rachelle Ihly,Jeffrey L Blackburn

doi:10.1038/s41467-017-01842-4

Lance M Wheeler, Nathan R Neale + Show 6 more

Open Access

https://doi.org/10.1038/s41467-017-01842-4

Copy DOI

Journal: Nature Communications	Publication Date: Nov 23, 2017
Citations: 117	License type: open-access

Affiliation: National Renewable Energy Laboratory

Abstract

Materials with switchable absorption properties have been widely used for smart window applications to reduce energy consumption and enhance occupant comfort in buildings. In this work, we combine the benefits of smart windows with energy conversion by producing a photovoltaic device with a switchable absorber layer that dynamically responds to sunlight. Upon illumination, photothermal heating switches the absorber layer—composed of a metal halide perovskite-methylamine complex—from a transparent state (68% visible transmittance) to an absorbing, photovoltaic colored state (less than 3% visible transmittance) due to dissociation of methylamine. After cooling, the methylamine complex is re-formed, returning the absorber layer to the transparent state in which the device acts as a window to visible light. The thermodynamics of switching and performance of the device are described. This work validates a photovoltaic window technology that circumvents the fundamental tradeoff between efficient solar conversion and high visible light transmittance that limits conventional semitransparent PV window designs.

Highlights

Materials with switchable absorption properties have been widely used for smart window applications to reduce energy consumption and enhance occupant comfort in buildings
This phenomenon circumvents the fundamental tradeoff observed in conventional semitransparent PV window designs[22,23,24], which sacrifice solar-to-electricity power conversion efficiency (PCE) for the high visible light transmittance critical for window performance[25]
The devices feature solar energy conversion efficiencies as high as 11.3% in the colored state, high visible light transmittance (68%) in the bleached state, reversible switching over 20 cycles, low switching temperature accessible by solar irradiation in most climates, and fast switching time

Summary

Introduction

Materials with switchable absorption properties have been widely used for smart window applications to reduce energy consumption and enhance occupant comfort in buildings. The intercalated compounds are stabilized by the formation of ionic[3,4], charge-transfer complex[5,6], van der Waals[7,8] and π-stacked fluorylaryl-aryl bonds[9] The weaker of these bonds are reversibly formed and dissociated with small energy input. The device is sealed in a closed atmosphere of dilute (2%) CH3NH2 gas in argon and returns to its complexed, bleached state upon removing the solar irradiation and cooling to re-form CH3NH3PbI3xCH3NH2 This phenomenon circumvents the fundamental tradeoff observed in conventional semitransparent PV window designs[22,23,24], which sacrifice solar-to-electricity power conversion efficiency (PCE) for the high visible light transmittance critical for window performance[25]. Coupled with the cost-effective, scalable solution-phase processing of lead halide perovskites, this technology widely expands the opportunity for energy-efficient PV deployment beyond solar farms and rooftops to glass building facades and vehicles

Methods

Results

Conclusion