Near-infrared photodetection based on PbS colloidal quantum dots/organic hole conductor

Abstract We have developed Near-infrared (NIR)-sensitive heterojunction cells consisting of n-type PbS colloidal quantum dots (CQDs) (low bandgap) anchored on the nanoporous TiO2 (np-TiO2, high-bandgap), and p-type spiro-OMeTAD (2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene). In these cells, an n-type np-TiO2 layer acts both as a host that chemically binds to the PbS CQDs and as an electron carrier. The number of PbS CQDs loaded onto the np-TiO2 layer not only increases the external quantum efficiency (EQE) but also reduces the response time in the NIR region. The performance of these devices increased upon the introduction of a TiOx layer between the PbS CQDs and spiro-OMeTAD followed by heat treatment at 110 °C for 1 min.

[1]  Soeren Steudel,et al.  Nanoparticle-based, spray-coated silver top contacts for efficient polymer solar cells , 2009 .

[2]  K. Choudhury,et al.  Efficient solution-processed hybrid polymer–nanocrystal near infrared light-emitting devices , 2010 .

[3]  G. Konstantatos,et al.  Smooth‐Morphology Ultrasensitive Solution‐Processed Photodetectors , 2008 .

[4]  D. B. Chesnokova,et al.  Effect of Oxidation Conditions on the Phase Composition, Structure, and Properties of Photosensitive Lead Sulfide Layers , 2001 .

[5]  Gregory D. Scholes,et al.  Colloidal PbS Nanocrystals with Size‐Tunable Near‐Infrared Emission: Observation of Post‐Synthesis Self‐Narrowing of the Particle Size Distribution , 2003 .

[6]  Tymish Y. Ohulchanskyy,et al.  Efficient photoconductive devices at infrared wavelengths using quantum dot-polymer nanocomposites , 2005 .

[7]  G. Konstantatos,et al.  Ultrasensitive solution-cast quantum dot photodetectors , 2006, Nature.

[8]  R. Schaller,et al.  High efficiency carrier multiplication in PbSe nanocrystals: implications for solar energy conversion. , 2004, Physical review letters.

[9]  Byung-Ryool Hyun,et al.  Electron injection from colloidal PbS quantum dots into titanium dioxide nanoparticles. , 2008, ACS nano.

[10]  F. Willig,et al.  Influence of trap filling on photocurrent transients in polycrystalline TiO2 , 1991 .

[11]  Max Shtein,et al.  Organic photodetector with spectral response tunable across the visible spectrum by means of internal optical microcavity , 2009 .

[12]  Sailing He,et al.  Imaging pancreatic cancer using surface-functionalized quantum dots. , 2007, The journal of physical chemistry. B.

[13]  Jun-Ho Yum,et al.  CdSe Quantum Dot-Sensitized Solar Cells Exceeding Efficiency 1% at Full-Sun Intensity , 2008 .

[14]  Larissa Levina,et al.  Fast, sensitive and spectrally tuneable colloidal-quantum-dot photodetectors. , 2009, Nature nanotechnology.

[15]  D Letalick,et al.  All-Fiber Multifunction Continuous-Wave Coherent Laser Radar at 1.55 num for Range, Speed, Vibration, and Wind Measurements. , 2000, Applied optics.

[16]  Gary Hodes,et al.  Comparison of Dye-and Semiconductor-Sensitized Porous Nanocrystalline Liquid Junction Solar Cells , 2008 .

[17]  S. Haque,et al.  PbS and CdS Quantum Dot‐Sensitized Solid‐State Solar Cells: “Old Concepts, New Results” , 2009 .