Broadband Sensitized Near‐Infrared Quantum Cutting Materials for Silicon Solar Cells: Progress, Challenges, and Perspectives

Abstract

Silicon solar cells are currently the most widely used type, accounting for more than 90% of the commercial market. However, the spectral mismatch between the solar spectrum and the absorption spectra of the cells is the main cause restricting their conversion efficiency, which can not exceed the Shockley‐Queisser limit. Quantum cutting can convert one high‐energy photon into two or more low‐energy photons and reduce the energy loss of the high‐energy photons, providing a way to improve the photoelectric conversion efficiency (PCE) of silicon solar cells. The unique electronic configuration of rare‐earth elements gives them excellent optical properties and makes them good candidates for the luminescent centers of quantum cutting materials. This paper reviews their luminescence mechanism, energy transfer (ET) mechanism, and application in silicon solar cells and outlines the potential problems of broadband‐sensitized NIR quantum cutting materials. Some key issues and future directions are also discussed.This article is protected by copyright. All rights reserved.

Broadband sensitized near‐infrared emission in Eu2+‐Nd3+ co‐doped BaAl2O4 as a potential spectral modulator for silicon solar cells

“…The emission intensity of Eu 2+ declines with increasing temperature as a result of temperature quenching. The reason is that when the temperature approaches absolute zero, the lattice vibrations are so weak that they hardly induce nonradiative transitions [15]. Figure 7b presents the integral area ratios of the emission spectra at various temperatures to the integral area at 80 K. We can estimate that approximately 60.91% of the excited Eu 2+ ions undergo radiative decay at room temperature, and therefore, the luminescence efficiency of Eu 2+ (η Eu ) is equal to 60.91%.…”

“…The energy migrates between the unradiated Eu 2+ until it is transferred to the quenching center (defects, impurities, etc.). In addition, lattice defects caused by excessive doping can also affect the emission intensity [15]. It can be realized that the emission intensity at 500 nm gradually decreases with the growth of Nd 3+ concentration, which is owing to the existence of ET from Eu 2+ to Nd 3+ .…”

“…The selection of sensitizers with broadband absorption is considered to be an effective way to solve this puzzle. Eu 2+ has broadband absorption induced by the 4f-5d transition and can be used as the sensitizer of Nd 3+ to enhance its utilization of UV-visible light [15,18]. During this process, Eu 2+ absorbs energy and transfers it to Nd 3+ , resulting in NIR emission.…”

“…Although Ce 3+ has the characteristics of broadband sensitization, there is a problem of low photon utilization between the two absorption peaks [12,14]. Nd 3+ possesses abundant energy levels, which facilitates the acquisition of more energy from the sensitizer due to the resonance energy transfer effect [15,16].…”