Effect of buffer layers on the performance of organic photovoltaic cells based on copper phthalocyanine and C60

Abstract The interface formed between fullerene (C 60 ) and cathode is a potential limiting factor to the performance of organic photovoltaic (OPV) cells based on copper phthalocyanine (CuPc)/C 60 heterojunctions. The influence of buffer layer on the performance of OPV cells was studied by usingbathophenanthroline (Bphen), 1,3,5-tris(2-N-phenylbenzimidazolyl) benzene (TPBi) and tris-8-hydroxy-quinolinato aluminum (Alq 3 ) to substitute for the bathocuproine (BCP) buffer layer between C 60 and Ag. It was found that the devices with different buffer layers exhibited both improved photovoltaic response and lower series resistance. Also, the defect states in the buffer layer indicate that buffer layers with appropriate film thickness can protect C 60 film from deterioration during Ag deposition and effectively improve charge carrier transportability. In addition, device stability has also been enhanced, particularly devices with Bphen and TPBi as buffer layers have achieved a shelf-lifetime of 1700 min in air at ambient circumstance.

[1]  F. Krebs,et al.  Analysis of the failure mechanism for a stable organic photovoltaic during 10 000 h of testing , 2007 .

[2]  Stephen R. Forrest,et al.  Very-high-efficiency double-heterostructure copper phthalocyanine/C60 photovoltaic cells , 2001 .

[3]  F. Krebs,et al.  Stability/degradation of polymer solar cells , 2008 .

[4]  Jianmin Shi,et al.  An Efficient Pure Blue Organic Light-Emitting Device with Low Driving Voltages , 2002 .

[5]  X. D. Gao,et al.  Small-molecular organic solar cells with C60/Al composite anode , 2007 .

[6]  Chun-Sing Lee,et al.  Doping-induced efficiency enhancement in organic photovoltaic devices , 2007 .

[7]  Junsheng Yu,et al.  Organic Photovoltaic Cells with Improved Performance Using Bathophenanthroline as a Buffer Layer , 2010 .

[8]  Barry P Rand,et al.  On the Role of Bathocuproine in Organic Photovoltaic Cells , 2008 .

[9]  Xiong Gong,et al.  Thermally Stable, Efficient Polymer Solar Cells with Nanoscale Control of the Interpenetrating Network Morphology , 2005 .

[10]  B. Kippelen,et al.  Intensity-dependent equivalent circuit parameters of organic solar cells based on pentacene and C60 , 2005 .

[11]  Chunhui Huang,et al.  Small-molecule organic solar cells with improved stability , 2005 .

[12]  Chun-Sing Lee,et al.  Efficient organic photovoltaic devices using a combination of exciton blocking layer and anodic buffer layer , 2006 .

[13]  Stephen R. Forrest,et al.  Efficient photon harvesting at high optical intensities in ultrathin organic double-heterostructure photovoltaic diodes , 2000 .

[14]  N. E. Coates,et al.  Efficient Tandem Polymer Solar Cells Fabricated by All-Solution Processing , 2007, Science.

[15]  Kahn,et al.  Chemistry and electronic properties of metal-organic semiconductor interfaces: Al, Ti, In, Sn, Ag, and Au on PTCDA. , 1996, Physical review. B, Condensed matter.

[16]  Hamed,et al.  Effects of oxygen and illumination on the in situ conductivity of C60 thin films. , 1993, Physical review. B, Condensed matter.

[17]  Albert Rose,et al.  Concepts in photoconductivity and allied problems , 1963 .

[18]  Frederik C. Krebs,et al.  A brief history of the development of organic and polymeric photovoltaics , 2004 .

[19]  Chunhui Huang,et al.  Stable small-molecule organic solar cells with 1,3,5-tris(2-N-phenylbenzimidazolyl) benzene as an organic buffer , 2007 .

[20]  R. Franke,et al.  Long-term stability of tandem solar cells containing small organic molecules , 2008 .

[21]  Stephen R. Forrest,et al.  Small molecular weight organic thin-film photodetectors and solar cells , 2003 .

[22]  C. M. Li,et al.  Role of buffer in organic solar cells using C60 as an acceptor , 2007 .

[23]  Junsheng Yu,et al.  Detailed analysis of bathocuproine layer for organic solar cells based on copper phthalocyanine and C60 , 2009 .

[24]  A. J. Heeger,et al.  Photoinduced Electron Transfer from a Conducting Polymer to Buckminsterfullerene , 1992, Science.

[25]  Ching Wan Tang,et al.  Organic electroluminescent devices with improved stability , 1996 .