Anode Interfacial Tuning via Electron-Blocking/Hole-Transport Layers and Indium Tin Oxide Surface Treatment in Bulk-Heterojunction Organic Photovoltaic Cells
✍ Scribed by Alexander W. Hains; Jun Liu; Alex B. F. Martinson; Michael D. Irwin; Tobin J. Marks
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 486 KB
- Volume
- 20
- Category
- Article
- ISSN
- 1616-301X
No coin nor oath required. For personal study only.
✦ Synopsis
The effects of anode/active layer interface modification in bulk-heterojunction organic photovoltaic (OPV) cells is investigated using poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and/or a holetransporting/electron-blocking blend of 4,4(-bis[( p-trichlorosilylpropylphenyl)phenylamino]biphenyl (TPDSi 2 ) and poly [9,9-dioctylfluorene-co-N-[4-(3methylpropyl)]-diphenylamine] (TFB) as interfacial layers (IFLs). Currentvoltage data in the dark and AM1.5G light show that the TPDSi 2 :TFB IFL yields MDMO-PPV:PCBM OPVs with substantially increased open-circuit voltage (V oc ), power conversion efficiency, and thermal stability versus devices having no IFL or PEDOT:PSS. Using PEDOT:PSS and TPDSi 2 :TFB together in the same cell greatly reduces dark current and produces the highest V oc (0.91 V) by combining the electron-blocking effects of both layers. ITO anode pre-treatment was investigated by X-ray photoelectron spectroscopy to understand why oxygen plasma, UV ozone, and solvent cleaning markedly affect cell response in combination with each IFL. O 2 plasma and UV ozone treatment most effectively clean the ITO surface and are found most effective in preparing the surface for PEDOT:PSS deposition; UV ozone produces optimum solar cells with the TPDSi 2 :TFB IFL. Solvent cleaning leaves significant residual carbon contamination on the ITO and is best followed by O 2 plasma or UV ozone treatment.