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Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization
Published on: January 29, 2017
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Squaraine based solution processed inverted bulk heterojunction solar cells processed in air.
P C Reshmi Varma1, Manoj A G Namboothiry1
1School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Engineering College P O, Thiruvananthapuram, Kerala PIN 695016, India. manoj@iisertvm.ac.in.
Physical Chemistry Chemical Physics : PCCP
|October 2, 2015
Summary
This study presents inverted bulk heterojunction solar cells using squaraine (SQ) and PC71BM. Optimized devices achieved a 4.12% power conversion efficiency, demonstrating potential for efficient solar energy conversion.
Area of Science:
- Materials Science
- Renewable Energy
- Organic Electronics
Background:
- Bulk heterojunction (BHJ) solar cells offer a promising route for low-cost photovoltaic applications.
- Solution-processed organic materials are attractive for large-scale solar cell fabrication.
Purpose of the Study:
- To investigate the performance of inverted BHJ solar cells based on squaraine (SQ) and [6,6]-phenyl C71 butyric acid methyl-ester (PC71BM).
- To optimize the blend ratio of SQ:PC71BM for enhanced power conversion efficiency (PCE).
- To analyze the recombination mechanisms and stability of the fabricated solar cells.
Main Methods:
- Fabrication of inverted BHJ solar cells using low-temperature solution processing of SQ and PC71BM in air.
- Varying the blend ratios of SQ and PC71BM to identify optimal device performance.
- Characterization of photovoltaic properties including power conversion efficiency (PCE), incident photon to current conversion efficiency (IPCE), and photocurrent under AM1.5G illumination.
- Analysis of intensity-dependent photocurrent to determine recombination mechanisms.
- Assessment of device stability under ambient conditions.
Main Results:
- An optimized SQ:PC71BM blend ratio of 1:6 yielded a PCE of 2.45% with high IPCE (65% at 680 nm) and a broad spectral response into the near-infrared (NIR) region.
- The optimized devices exhibited an enhanced PCE of 4.12% under continuous AM1.5G illumination.
- Photocurrent studies indicated a monomolecular recombination mechanism governing the photovoltaic performance.
- The solar cells demonstrated reasonable stability, maintaining performance for one month when stored in air.
Conclusions:
- Low-temperature solution-processed inverted BHJ solar cells based on SQ and PC71BM can achieve significant power conversion efficiencies.
- The optimized blend ratio and device architecture are crucial for maximizing solar cell performance.
- Understanding the recombination dynamics is key to further improving device efficiency and stability.
