Identifying the Issue
Perovskite solar cells (PSCs) are among the most promising next-generation photovoltaic technologies; however, their large-scale commercialization is hindered by the high cost, limited thermal stability, and significant interfacial energy losses associated with conventional hole-transport materials (HTMs), such as spiro-OMeTAD. Addressing these challenges requires the development of cost-effective, thermally robust, and highly efficient HTMs. This work demonstrates a rational molecular engineering strategy that enhances intramolecular charge transfer (ICT), optimizes energy-level alignment, and promotes defect passivation at the perovskite interface, resulting in improved device efficiency and long-term stability.
Objective of the Research
This work aimed to design and develop two novel electron-deficient tricyanofuran (TCF)-based hole-transport materials, RK7 and RK8, for high-performance perovskite solar cells. Density Functional Theory (DFT) and Time-Dependent DFT (TDDFT) calculations were employed to investigate their electronic structures, energy-level alignment, charge-transfer characteristics, and excited-state properties. The designed materials were subsequently synthesized, purified, and comprehensively characterized to evaluate their thermal, optical, electrochemical, photophysical, and charge-transport properties. Finally, perovskite solar cells incorporating RK7 and RK8 as hole-transport materials were fabricated and tested to assess their photovoltaic performance, defect passivation capability, and long-term operational stability.
Who should read this?
Faculty members, researchers, graduate students, and professionals working in the fields of Materials Chemistry, Energy Materials, Solar Energy Conversion, Organic Electronics, Computational Chemistry, and Materials Design.
Solution
The rational design of advanced hole-transport materials (HTMs) is essential for improving the efficiency and stability of perovskite solar cells (PSCs). In this study, two novel tricyanofuran (TCF)-based HTMs, RK7 and RK8, were designed through a synergistic combination of DFT-guided molecular engineering and experimental validation. Incorporating an electron-deficient TCF acceptor significantly enhanced π-conjugation and intramolecular charge transfer, leading to favorable energy-level alignment and reduced interfacial energy losses. Both HTMs exhibited strong Lewis basicity, enabling effective defect passivation and improved perovskite film quality. Among them, RK8 demonstrated superior thermal stability (Td > 275 °C), higher hole mobility (1.15 × 10⁻³ cm² V⁻¹ s⁻¹), and enhanced conductivity (1.50 × 10⁻⁵ S cm⁻¹). PSCs employing RK8 achieved a champion power conversion efficiency (PCE) of 17.29%, minimal hysteresis (1.56%), and retained over 80% of their initial efficiency after 1512 hours, highlighting its potential as a durable and high-performance HTM for next-generation PSCs.
Key Features and Benefits
- Development of two novel donor–acceptor HTMs, RK7 and RK8, for efficient and stable perovskite solar cells.
- Demonstration of excellent agreement between DFT/TDDFT predictions and experimental observations, validating the computational design strategy.
- Enhanced π-conjugation and intramolecular charge transfer through incorporation of the electron-deficient TCF acceptor.
- Improved hole mobility, conductivity, thermal stability, and defect passivation characteristics compared to conventional HTMs.
- Provides a cost-effective molecular engineering approach for developing durable, high-performance PSCs
Impact
- High Device Efficiency: RK8-based PSCs achieved a champion PCE of 17.29%.
- Reduced Hysteresis: Devices exhibited a low hysteresis index of 1.56%, indicating efficient charge extraction and reduced defect-assisted recombination losses.
- Outstanding Stability: RK8-based PSCs retained more than 80% of their initial efficiency after 1512 hours of storage.
- Accelerated Materials Discovery: Strong agreement between theoretical predictions and experimental results demonstrates the effectiveness of DFT-guided materials design.
- Advancing Sustainable Energy: The developed HTMs offer a promising pathway toward commercially viable, stable, and high-performance perovskite solar technologies
Team
Ravikumar Gurusamy, Vidya Sudhakaran Menon, Mainak Mukherjee, Gowri Chandran Chandrakumar Veena, Sivasankar Parameswaran, Arya Kamal, Karnamaharaja Duraimani, Gurusamy Thangavelu Senthil Andavan, V. N. Ravi Kishore Vutukuri*, and Ananthanarayanan Krishnamoorthy*
Title of paper: “Rational Design of Electron-Deficient Tricyanofuran-Based Hole Transport Materials for Stable Perovskite Solar Cells: Combined DFT and Experimental Insights”
Read Paper Here: https://doi.org/10.1021/acsaem.6c00552