Unravelling the Abnormal Thermo-Mechanical Behavior of 2D Hybrid Organic-Inorganic Perovskites

Texas A&M Engineering Experiment Station, College Station TX

Investigators

Abstract

This award supports research which aims to investigate how temperature influences the mechanical behavior of 2D hybrid organic-inorganic perovskites and uncover the origin of such thermo-mechanical behavior. These materials are burgeoning low-cost, high-performance semiconductor materials with great potential in various energy and electronics applications, including solar cells, transistors, sensors, and flexible electronics. The coexistence of mechanical strain and temperature fluctuations is universally found in such applications and causes mechanical failure issues that significantly hinder commercial viability. However, the thermo-mechanical behavior of 2D hybrid organic-inorganic perovskites remains elusive. This research project will bridge this knowledge gap by systematically measuring the mechanical property change of these materials as a function of temperature using atomic force microscopy. The findings of this research have the potential to extend the lifetime of energy and electronic devices using 2D hybrid organic-inorganic perovskites. Additionally, it can expedite the commercialization of low cost and efficient solar cells made of these materials, greatly facilitating the realization of the US government’s clean energy goals. This project will also provide opportunities to educate and train graduate and undergraduate students at Texas A&M University, a Hispanic Serving Institute, and promote STEM education/careers through on-campus K-12 and community outreach activities. 2D hybrid organic-inorganic perovskites manifest a uniquely different in-plane thermo-mechanical behavior compared to their 3D counterparts or other low-dimensional materials. The overarching goal of this project is to form a fundamental and comprehensive understanding of the thermo-mechanical behavior and unveil the structural origin found in 2D hybrid organic-inorganic perovskites. Advanced scanning probe-based nanomechanical characterization techniques at controlled temperatures will be employed to systematically investigate the temperature-dependent mechanical properties of these materials along both in-plane and out-of-plane directions. The project will test the central hypothesis that the thermal response of the organic spacer molecules and their interfaces give rise to the interesting thermo-mechanical behavior of 2D hybrid organic-inorganic perovskites. The thermal response of the organic spacer molecules will be engineered by tuning the structural parameters of 2D hybrid organic-inorganic perovskites, and directly correlated to the attendant thermo-mechanical behavior of the materials, where the mechanistic explanation will be provided by the interfacial shear strength between the 2D layers measured with friction force microscopy. The research outcomes will offer indispensable insights to engineer, design, and optimize mechanical reliability and the strain-coupled semiconductor performance of 2D hybrid organic-inorganic perovskites across the technologically interested temperature range. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.