Open-Circuit Voltage Losses in Selenium-Substituted Organic Photovoltaic Devices from Increased Density of Charge-Transfer States
Open-Circuit Voltage Losses in Selenium-Substituted Organic Photovoltaic Devices from Increased Density of Charge-Transfer States
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DOI：
10.1021/acs.chemmater.5b02133
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发表时间：
2015-09
影响因子：
8.6
通讯作者：
Dana B. Sulas;Kai Yao;Jeremy J. Intemann;Spencer T. Williams;Chang‐Zhi Li;Chu‐Chen Chueh;J. J. Richards-J.;Yuyin Xi;L. Pozzo;Cody W. Schlenker;A. Jen;D. Ginger
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文献类型：
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作者：
Dana B. Sulas;Kai Yao;Jeremy J. Intemann;Spencer T. Williams;Chang‐Zhi Li;Chu‐Chen Chueh;J. J. Richards-J.;Yuyin Xi;L. Pozzo;Cody W. Schlenker;A. Jen;D. Ginger
使用基于Marcus理论的分析，我们表征了由于电荷转移态能量、电子耦合和电荷转移态空间密度的变化而导致的开路电压（VOC）损失，这些变化发生在一系列聚合物/富勒烯太阳能电池中。我们使用一系列的引达省并二噻吩聚合物及其硒取代类似物作为电子给体材料，富勒烯作为受体。通过结合设备的测量和光谱研究（包括亚隙光电流，电致发光，重要的是，时间分辨的电荷转移态的光致发光），我们能够隔离的值为电子耦合和电荷转移态（NCT）的密度，而不是更常见的测量这些值的产品。我们发现NCT的值令人惊讶地大（约4.5 × 1021-6.2 × 1022 cm-3），并且我们发现在供体聚合物中硒取代后NCT的显著增加与本体异质结光伏器件的较低VOC相关。公司简介
Using an analysis based on Marcus theory, we characterize losses in open-circuit voltage (VOC) due to changes in charge-transfer state energy, electronic coupling, and spatial density of charge-transfer states in a series of polymer/fullerene solar cells. We use a series of indacenodithiophene polymers and their selenium-substituted analogs as electron donor materials and fullerenes as the acceptors. By combining device measurements and spectroscopic studies (including subgap photocurrent, electroluminescence, and, importantly, time-resolved photoluminescence of the charge-transfer state) we are able to isolate the values for electronic coupling and the density of charge-transfer states (NCT), rather than the more commonly measured product of these values. We find values for NCT that are surprisingly large (∼4.5 × 1021–6.2 × 1022 cm–3), and we find that a significant increase in NCT upon selenium substitution in donor polymers correlates with lower VOC for bulk heterojunction photovoltaic devices. The inc...