April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)

Event Supporters

2024 MRS Spring Meeting
EN11.01.01

Experiments toward High-Performance Zintl Phosphide Solar Absorbers

When and Where

Apr 24, 2024
1:30pm - 2:00pm
Room 335, Level 3, Summit

Presenter(s)

Co-Author(s)

Sage Bauers1,Obadiah Reid1,David Fenning2,Andriy Zakutayev1,Jifeng Liu3,Kirill Kovnir4,Geoffroy Hautier3

National Renewable Energy Laboratory1,University of California, San Diego2,Dartmouth College3,Iowa State University of Science and Technology4

Abstract

Sage Bauers1,Obadiah Reid1,David Fenning2,Andriy Zakutayev1,Jifeng Liu3,Kirill Kovnir4,Geoffroy Hautier3

National Renewable Energy Laboratory1,University of California, San Diego2,Dartmouth College3,Iowa State University of Science and Technology4
Most photovoltaic absorber materials development is done on materials with known or slightly modified structural prototypes; for example, kesterite, chalcopyrite, and zincblende are all derived from mutations to the diamond crystal structure. It is rare and sometimes transformative—such as in halide perovskites—when new structural classes of absorber materials are discovered. The <i>AM</i><sub>2</sub>P<sub>2</sub> (<i>A</i> = alkaline earth cation such as Ba, Ca, Sr and <i>M</i> = 2+ cation such as Zn, Cd) compounds have previously been described as semiconducting zintl phases and are structurally distinct to widely studied PV materials. However, these have attracted recent interest from theory as materials with solar-spectrum matched band gaps and tolerance to intrinsic point defects. BaCd<sub>2</sub>P<sub>2</sub> is particularly compelling with a direct 1.45 eV band gap and mostly comprising inexpensive elements already used in solar absorber applications, thus having high-grade feedstocks already available. Here, we report on the synthesis and properties of BaCd<sub>2</sub>P<sub>2</sub> and related <i>AM</i><sub>2</sub>P<sub>2</sub> materials. BaCd<sub>2</sub>P<sub>2</sub> can be synthesized in powder form from elemental precursors using conventional solid-state reaction methods. The material forms in a <i>P</i>-3<i>m</i>1 crystal structure (CaAl<sub>2</sub>Si<sub>2</sub> prototype) and is stable in open air heating up to 300 °C as well as in acids, bases, and at even higher temperatures in inert environments. BaCd<sub>2</sub>P<sub>2</sub> powder shows strong band-to-band photoluminescence that is stable at elevated temperature and time-resolved microwave conductivity shows long photoexcited carrier lifetimes of around 30 ns, which is already longer than observed in some much more mature absorber technologies. Since the direct-gap <i>AM</i><sub>2</sub>P<sub>2</sub> materials will be most compelling as thin film absorbers, we also discuss several ongoing efforts to realize these compounds in thin film format.

Keywords

P

Symposium Organizers

Andrea Crovetto, Technical University of Denmark
Annie Greenaway, National Renewable Energy Laboratory
Xiaojing Hao, Univ of New South Wales
Vladan Stevanovic, Colorado School of Mines

Session Chairs

Andrea Crovetto
Xiaojing Hao

In this Session