Tuning the charge blocking layer to enhance photomultiplication in organic shortwave infrared photodetectors
Tuning the charge blocking layer to enhance photomultiplication in organic shortwave infrared photodetectors
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DOI：
10.1039/d0tc03013a
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发表时间：
2020-11-21
影响因子：
6.4
通讯作者：
Ng, Tse Nga
中科院分区：
文献类型：
--
作者：
Li, Ning;Lim, Jasmine;Ng, Tse Nga
新兴的红外光电探测器已经报道了高水平的增益使用陷阱辅助光电倍增机制，使其灵敏度显着增强。这项工作研究了一系列界面材料，以了解电荷阻挡层如何促进有机短波红外探测器中的陷阱辅助光电倍增。空穴阻挡层在界面处诱导光生空穴的积累，从而降低电子注入势垒，使光电倍增成为可能。除了检测光响应特性外，还通过拟合电荷注入模型来分析器件的暗电流，以量化注入势垒。这表明电场诱导的势垒降低效应随着外加偏置的增加而趋于平稳。在所研究的界面中，使用空穴阻挡层邻苯二甲酸乙酯（Bphen）观察到最好的探测性，它降低了重组的概率，延长了被困空穴的寿命，从而增加了光电倍增。这导致响应率为5.6 a W-1（等效外量子效率= 660%，在1050 nm），探测率为10(9)琼斯，宽带操作从600 nm到1400 nm。
Emerging infrared photodetectors have reported a high level of gain using trap-assisted photomultiplication mechanisms enabling significant enhancements in their sensitivity. This work investigates a series of interfacial materials in order to understand how charge blocking layers facilitate trap-assisted photomultiplication in organic shortwave infrared detectors. The hole blocking layers induce accumulation of photogenerated holes at the interface, which in turn lowers the electron injection barrier and enables photomultiplication. In addition to examining photoresponse characteristics, the device dark current is analyzed by fitting to a charge injection model to quantify injection barriers. This demonstrates that the electric field induced barrier lowering effect plateaus with increasing applied bias. Among the interfaces studied, the best detectivity is observed using the hole blocking layer bathophenanthroline (Bphen), which reduces the probability of recombination and extends the lifetime of trapped holes to increase photomultiplication. This leads to a responsivity of 5.6 A W-1 (equivalent external quantum efficiency = 660% at 1050 nm) and detectivity of 10(9) Jones with broadband operation from 600 nm to 1400 nm.