甲胺钙钛矿晶体光致荧光增强作用机制:光生载流子激发的超氧根离子对表面和体内的缺陷修复
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- 论文作者：何祝兵 ; 冯溪渊 ; 易婷婷
- 年：2017
- 作者机构：南方科技大学材料系深圳市全光谱功能材料重点实验室(FSSEG);
- 会议召开时间：2017-05-27
- 会议录名称：第四届新型太阳能电池学术研讨会论文集
- 英文会议录名称：Abstract Book of the 4th Conference on New Generation Solar Cells
- 语种：中文
- 分类号：O734
- 学会代码：ZKYQ
- 会议名称：第四届新型太阳能电池学术研讨会
- 会议地点：中国北京
- 主办单位：中国可再生能源学会光化学专业委员会
- 学会名称：中国科学院物理研究所清洁能源实验室
- 页数：1
- 文件大小：608k
- 原文格式：D
- 会议级别：全国
摘要
目的:揭示光对空气中有机无机杂化钙钛矿的作用机制始终是设计和优化钙钛矿光电器件的一项重要工作。尽管大家已经形成共识,即具有光照射下氧气分子是对钙钛矿光致发光(PL)增强效应的主要因素。然而,迄今为止,关于光、氧气分子和钙钛矿材料相互作用的具体机制仍在争论之中。方法:在本工作中,我们基于激光共聚焦显微镜平台,系统性研究了甲胺钙钛矿单晶在不同辐照光强(从8.7μJ/cm~2到217μJ/cm~2)、不同激光波长(532nm、778nm、808nm和980nm)、不同气氛环境(真空、空气、纯氧、纯氮和纯氩)以及环境变化、不同深度梯度下的荧光(PL)增强效应。值得注意的是,我们采用处于缺陷辅助复合机制光强(15-40μW)的532nm激光作为PL激发光源。结果:首先随着辐照光强的增强,钙钛矿晶体载流子复合呈现单分子、双分子和俄歇复合三个阶段。室温下PL峰中心位置为776nm。光照波长和环境种类依赖的PL增强结果显示了光子生成载流子和氧气分子起到不可或缺的作用。令人吃惊的是,氧气分子在晶体内100微米深度仍然可以导致荧光增强,而且在短暂无光照条件下载流子没有快速覆灭。这种现象说明仅仅氧原子扩散作用无法解释这种现象。结论:基于本工作系统而又直接的数据,我们提出由光生自由电子与氧气分子发生黏附反应生成的O~(2-)离子是钙钛矿材料荧光增强效应的根本原因。它在在扩散和晶体场作用下快速渗透,钝化钙钛矿体内的缺陷(如甲胺和碘空位、游离离子等),降低非发光性复合几率,实现荧光增强。该工作将进一步加深人们对这一重要机制的理解。
It is always essential for designing and optimizing devices to discover the interaction mechanism of light on hybrid perovskite materials in air.However, the mechanism is still on debate so far although it is already a consensus that oxygen gas molecules with light irradiation contribute predominantly to photoluminescence(PL) enhancements in the perovskite crystals.In this work, a 532 nm laser with 15-40μW(in defect assisted recombination stage) was employed to measure PL enhancements depending on light intensity, wavelength, with or without oxygen atmosphere, environment variation and transfer, and in the depth profile.The soaking light wavelength and environment kinds dependent PL enhancements results explicit the indispensable roles of photon-generated carriers and oxygen gas molecules separately.The PL enhancements with oxygen is so deep as over 100 um that demonstrate the penetration of oxygen species must be attributed to more than diffusion, and further the passivation of the oxygen species is so stable in such a long way and even in the blind of light soaking in contrast to that of carriers and neutral species only.On the basis of these solid data, we proposed that it is O_2~- ions, yielded from O_2 attached with free moving electrons, that penetrated with assistance of both diffusion and crystal field screening and made effect in all the related PL enhancements involved in our work and other literatures.This paper will definitely deepen our understanding of the interaction mechanism in this field.
It is always essential for designing and optimizing devices to discover the interaction mechanism of light on hybrid perovskite materials in air.However, the mechanism is still on debate so far although it is already a consensus that oxygen gas molecules with light irradiation contribute predominantly to photoluminescence(PL) enhancements in the perovskite crystals.In this work, a 532 nm laser with 15-40μW(in defect assisted recombination stage) was employed to measure PL enhancements depending on light intensity, wavelength, with or without oxygen atmosphere, environment variation and transfer, and in the depth profile.The soaking light wavelength and environment kinds dependent PL enhancements results explicit the indispensable roles of photon-generated carriers and oxygen gas molecules separately.The PL enhancements with oxygen is so deep as over 100 um that demonstrate the penetration of oxygen species must be attributed to more than diffusion, and further the passivation of the oxygen species is so stable in such a long way and even in the blind of light soaking in contrast to that of carriers and neutral species only.On the basis of these solid data, we proposed that it is O_2~- ions, yielded from O_2 attached with free moving electrons, that penetrated with assistance of both diffusion and crystal field screening and made effect in all the related PL enhancements involved in our work and other literatures.This paper will definitely deepen our understanding of the interaction mechanism in this field.
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