Enhanced Elastocaloric Effects in {\gamma}-graphyne

TL;DR

This study demonstrates that pre-straining { extgamma}-graphyne nanoribbons significantly enhances their elastocaloric effect, achieving large temperature changes and COP, indicating potential for sustainable cooling technologies.

Contribution

It provides the first detailed molecular dynamics analysis of elastocaloric effects in { extgamma}-graphyne, highlighting the impact of pre-strain and substrate conditions on performance.

Findings

Pre-strain amplifies elastocaloric effect by over tenfold.

Temperature change up to 224 K observed in { extgamma}-graphyne.

COP values reach as high as 14 under optimal conditions.

Abstract

The global emphasis on sustainable technologies has become a paramount concern for nations worldwide. Specifically, numerous sustainable methods are being explored as promising alternatives to the well-established vapor-compression technologies in cooling and heating devices. One such avenue gaining traction within the scientific community is the elastocaloric effect (eC). This phenomenon holds promise for efficient cooling and heating processes without causing environmental harm. Studies carried out at the nanoscale have demonstrated the efficiency of the eC, proving to be comparable to that of state-of-the-art macroscopic systems. In this study, we used classical molecular dynamics simulations to investigate the elastocaloric effect for {\gamma}-graphyne. Our analysis goes beyond obtaining changes in eC temperature and the coefficient of performance (COP) for two species of {\gamma}-graphyne nanoribbons (armchair and zigzag). We also explore their dependence on various conditions, including whether they are on deposited on a substrate or pre-strained. Our findings reveal a substantial enhancement in the elastocaloric effect for {\gamma}-graphyne nanoribbons when subjected to pre-strain, amplifying it by at least one order of magnitude. Under certain conditions, the change in the eC temperature and the COP of the structures reach expressive values as high as 224 K and 14, respectively. We discuss the implications of these results by examining the shape and behavior of the carbon-carbon bond lengths within the structures.