Phosphorene Nanoribbon-Augmented Optoelectronics for Enhanced Hole Extraction

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Phosphorene nanoribbons (PNRs) are predicted to have excellent functional properties for optoelectronics.
• These properties include high exciton binding energies, tunable bandgaps, and ultrahigh hole mobilities.
• Experimental verification of these properties and their application benefits is limited due to recent isolation of PNRs.

Purpose of the Study:

• To experimentally verify the theorized enhanced hole mobility of PNRs.
• To demonstrate the potential of PNRs in improving hole extraction for optoelectronic applications.
• To investigate the performance of PNRs as charge-selective interlayers in perovskite solar cells (PSCs).

Main Methods:

• Fabrication and characterization of planar p-i-n (inverted) perovskite solar cells (PSCs) with PNR interlayers.
• Utilizing space-charge-limited-current (SCLC) hole-only devices to measure hole mobility and conductivity.
• Employing device photoluminescence and transient absorption spectroscopy to analyze carrier extraction dynamics.

Main Results:

• PNRs significantly enhance hole extraction from methylammonium lead iodide (MAPbI₃) perovskite to poly(triarylamine).
• Inverted PSCs with PNR interlayers achieved fill factors > 0.83 and efficiencies > 21%, comparable to single-crystalline MAPbI₃ devices.
• PNR interlayers also improved performance in methylammonium-free PSCs and enhanced hole mobility and conductivity in SCLC devices.

Conclusions:

• This work provides the first experimental evidence that PNRs' predicted properties translate to improved optoelectronic device performance.
• PNRs serve as effective charge-selective interlayers, enhancing carrier extraction in universal optoelectronic applications.
• The findings highlight PNRs' potential for advancing next-generation optoelectronic devices, including PSCs.