Charge Carrier Lifetime Determination in Graded Absorber Solar Cells Using Time‐Resolved Photoluminescence Simulations and Measurements
- National Renewable Energy Laboratory Golden CO 80401 USA
- Department of Mechanical Engineering Colorado State University Fort Collins CO 80523 USA
- School of Electrical, Computer and Energy Engineering Arizona State University Tempe AZ 85287 USA
Thin‐film photovoltaic device efficiencies are limited by carrier recombination, thus understanding recombination mechanisms is critical for performance improvements. Bulk minority carrier lifetime ( τ bulk ) is a critical parameter for solar cells but is difficult to determine in P–N junction devices, especially for high doping. As doping ≥10 16 cm −3 is required for efficient drift‐charge‐carrier‐collection devices, a method for τ bulk determination in doped P–N junction devices is necessary. This work utilizes time‐resolved photoluminescence (TRPL) simulations to quantify bulk and interface recombination properties in highly doped, graded absorber CdSeTe structures. The two methods developed here for τ bulk determination include utilization of an instantaneous lifetime representation to guide TRPL fitting and direct comparison between measured and simulated decays. Simulations verified that both methods are valid for state‐of‐the‐art device architectures which include graded bandgap absorbers, graded doping, and graded lifetimes. Shifts in the dominant recombination mechanism are identified for sufficiently long τ bulk , where front and back interface quality plays a more prominent role. Evaluation of surface recombination velocities and conduction band offset illustrate electro‐optical advantages of a positive conduction band offset and highlight the necessity of improved interfaces as bulk quality in photovoltaic devices improves.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
- Grant/Contract Number:
- AC36-08GO28308; EE0008552
- OSTI ID:
- 1959083
- Alternate ID(s):
- OSTI ID: 1959085
OSTI ID: 1973679
- Report Number(s):
- NREL/JA-5900-84670; 2201029
- Journal Information:
- Solar RRL, Journal Name: Solar RRL Journal Issue: 9 Vol. 7; ISSN 2367-198X
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English