Effect of organic small-molecule hole injection materials on the performance of inverted organic solar cells

Abstract. In this study, the influence of small-molecule organic hole injection materials on the performance of organic solar cells (OSCs) as the hole transport layer (HTL) with an architecture of ITO/ZnO/P3HT:PC71BM/HTL/Ag has been investigated. A significant enhancement on the performance of OSCs from 1.06% to 2.63% is obtained by using N, N′-bis(1-naphthalenyl)-N, N′-bis-phenyl-(1, 1′-biphenyl)-4, 4′-diamine (NPB) HTL. Through the resistance simulation and space-charge limited current analysis, we found that NPB HTL cannot merely improve the hole mobility of the device but also form the Ohmic contact between the active layer and anode. Besides, when we apply mix HTL by depositing the NPB on the surface of molybdenum oxide, the power conversion efficiency of OSC are able to be further improved to 2.96%.

[1]  D. Bradley,et al.  Trap-free, space-charge-limited currents in a polyfluorene copolymer using pretreated indium tin oxide as a hole injecting contact , 2001 .

[2]  George G. Malliaras,et al.  Temperature- and field-dependent electron and hole mobilities in polymer light-emitting diodes , 1999 .

[3]  Junsheng Yu,et al.  Effect of two-step annealing on the performance of ternary polymer solar cells based on P3HT:PC71BM:SQ , 2014 .

[4]  Niyazi Serdar Sariciftci,et al.  REVERSIBLE, METASTABLE, ULTRAFAST PHOTOINDUCED ELECTRON TRANSFER FROM SEMICONDUCTING POLYMERS TO BUCKMINSTERFULLERENE AND IN THE CORRESPONDING DONOR/ACCEPTOR HETEROJUNCTIONS , 1994 .

[5]  Zakya H. Kafafi,et al.  Organic Photovoltaics: Plasmonic‐Enhanced Organic Photovoltaics: Breaking the 10% Efficiency Barrier (Adv. Mater. 17/2013) , 2013 .

[6]  Suren A. Gevorgyan,et al.  Scalability and stability of very thin, roll-to-roll processed, large area, indium-tin-oxide free polymer solar cell modules , 2013 .

[7]  F. Krebs,et al.  Low band gap polymers for organic photovoltaics , 2007 .

[8]  Wolfgang Kowalsky,et al.  The Role of Transition Metal Oxides in Charge‐Generation Layers for Stacked Organic Light‐Emitting Diodes , 2010 .

[9]  Junsheng Yu,et al.  Towards High Performance Organic Photovoltaic Cells: A Review of Recent Development in Organic Photovoltaics , 2014 .

[10]  Junsheng Yu,et al.  Effects of different polar solvents for solvent vapor annealing treatment on the performance of polymer solar cells , 2014 .

[11]  C. Deibel,et al.  The Effect of Diiodooctane on the Charge Carrier Generation in Organic Solar Cells Based on the Copolymer PBDTTT-C , 2015, Scientific Reports.

[12]  Junsheng Yu,et al.  Power efficiency enhancement of solution-processed small-molecule solar cells based on squaraine via thermal annealing and solvent additive methods , 2013 .

[13]  Min-Soo Choi,et al.  Fully vacuum–processed perovskite solar cells with high open circuit voltage using MoO3/NPB as hole extraction layers , 2015 .

[14]  Wolfgang Kowalsky,et al.  Role of the deep-lying electronic states of MoO3 in the enhancement of hole-injection in organic thin films , 2009 .

[15]  D. Zou,et al.  Carrier Mobilities in Organic Electron Transport Materials Determined from Space Charge Limited Current , 2001 .

[16]  A. Kahn,et al.  Effect of contamination on the electronic structure and hole-injection properties of MoO3/organic semiconductor interfaces , 2010 .

[17]  A. Kahn,et al.  P-type doping of organic wide band gap materials by transition metal oxides: A case-study on Molybdenum trioxide , 2009 .

[18]  Jianhui Hou,et al.  Low‐Temperature Solution‐Processed Hydrogen Molybdenum and Vanadium Bronzes for an Efficient Hole‐Transport Layer in Organic Electronics , 2013, Advanced materials.

[19]  Junsheng Yu,et al.  Effect of in situ annealing on the performance of spray coated polymer solar cells , 2013 .

[20]  Zheng-Hong Lu,et al.  Universal energy-level alignment of molecules on metal oxides. , 2011, Nature materials.

[21]  M. Chegaar,et al.  Solar cells parameters evaluation considering the series and shunt resistance , 2007 .

[22]  T. P. Russell,et al.  Multi‐Length‐Scale Morphologies in PCPDTBT/PCBM Bulk‐Heterojunction Solar Cells , 2012 .

[23]  Dong Lim Kim,et al.  Hole transport enhancing effects of polar solvents on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) for organic solar cells. , 2012, ACS applied materials & interfaces.

[24]  T. Yoon,et al.  Ohmic contact probed by dark injection space-charge-limited current measurements , 2008 .

[25]  Richa Pandey,et al.  Graded Donor‐Acceptor Heterojunctions for Efficient Organic Photovoltaic Cells , 2010, Advanced materials.

[26]  Yoshiki Kinoshita,et al.  Formation of Ohmic hole injection by inserting an ultrathin layer of molybdenum trioxide between indium tin oxide and organic hole-transporting layers , 2007 .

[27]  J. J. M. Vleggaar,et al.  Electron and hole transport in poly(p‐phenylene vinylene) devices , 1996 .

[28]  A. Kahn,et al.  Electronic structure of molybdenum-oxide films and associated charge injection mechanisms in organic devices , 2011 .

[29]  J. Jang,et al.  Relationship between indium tin oxide surface treatment and hole injection in C60 modified devices , 2006 .

[30]  Vladimir Dyakonov,et al.  Polymer–fullerene bulk heterojunction solar cells , 2010, 1003.0359.

[31]  Xingzhong Zhao,et al.  In situ growth of double-layer MoO3/MoS2 film from MoS2 for hole-transport layers in organic solar cell , 2014 .

[32]  S. Tsang,et al.  Polymeric conducting anode for small organic transporting molecules in dark injection experiments , 2006 .