Dual-Doping Improves Heterojunction and Homojunction Photo-Charge Utilization Toward Transmission Spectrum-Tailored...

Area of Science:

• Organic electronics
• Renewable energy technologies
• Photovoltaics

Background:

• Organic solar cells (OSCs) offer tunable spectra for agrivoltaics but face efficiency loss due to donor-reduced morphology.
• Optimizing active layer morphology is crucial for maximizing OSC performance in integrated systems.

Purpose of the Study:

• To address power conversion efficiency (PCE) loss in donor-reduced OSCs for agrivoltaic applications.
• To introduce a dual-doping strategy for enhanced charge transport and morphology control.
• To define and evaluate a comprehensive metric, total light utilization efficiency (LUEtotal), for agrivoltaic systems.

Main Methods:

• Employing p- and n-dopants (TrTPFB and P2-t-Bu) with selective affinities for donor and acceptor materials.
• Implementing a two-step sequential doping procedure for controlled dual-doping.
• Characterizing device performance and analyzing charge dynamics through mechanism studies.

Main Results:

• Achieved a significant PCE increase from 6.5% to 10.1% in D18:L8-BO (0.08:1) OSCs via dual-doping, outperforming singly doped devices.
• Demonstrated enhanced photo-charge utilization at both donor/acceptor heterojunctions and acceptor/acceptor homojunctions.
• Reported a champion total light utilization efficiency (LUEtotal) of 10.1% under over donor-reduced conditions, surpassing optimal BHJ and conventional ST-OSC conditions.

Conclusions:

• Dual-doping is an effective strategy to overcome PCE loss in donor-reduced OSCs for agrivoltaics.
• The novel LUEtotal metric provides a holistic evaluation of OSC performance in agrivoltaic settings.
• Optimized donor-reduced OSCs show superior integrated light utilization for combined energy and biomass production.