Konstantatos Gerasimos, Levina Larissa, Fischer Armin, Sargent Edward H
Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto ON M5S 3G4, Canada.
Nano Lett. 2008 May;8(5):1446-50. doi: 10.1021/nl080373e. Epub 2008 Apr 2.
Photoconductive photodetectors fabricated using simple solution-processing have recently been shown to exhibit high gains (>1000) and outstanding sensitivities ( D* > 10(13) Jones). One ostensible disadvantage of exploiting photoconductive gain is that the temporal response is limited by the release of carriers from trap states. Here we show that it is possible to introduce specific chemical species onto the surfaces of colloidal quantum dots to produce only a single, desired trap state having a carefully selected lifetime. In this way we demonstrate a device that exhibits an attractive photoconductive gain (>10) combined with a response time ( approximately 25 ms) useful in imaging. We achieve this by preserving a single surface species, lead sulfite, while eliminating lead sulfate and lead carboxylate. In doing so we preserve the outstanding sensitivity of these devices, achieving a specific detectivity of 10(12) Jones in the visible, while generating a temporal response suited to imaging applications.
最近研究表明，采用简单溶液处理制造的光电导探测器具有高增益（>1000）和出色的灵敏度（D* > 10(13) Jones）。利用光电导增益的一个明显缺点是时间响应受限于陷阱态中载流子的释放。在此我们表明，有可能在胶体量子点表面引入特定化学物种，以产生仅具有精心选择寿命的单一所需陷阱态。通过这种方式，我们展示了一种器件，它具有吸引人的光电导增益（>10），同时具有适用于成像的响应时间（约25毫秒）。我们通过保留单一表面物种亚硫酸铅，同时消除硫酸铅和羧酸铅来实现这一点。这样做时，我们保留了这些器件的出色灵敏度，在可见光下实现了10(12) Jones的比探测率，同时产生了适合成像应用的时间响应。
