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Dimensionality-driven decoupling of electronic-ionic transport in a Cs4PbBr6/CsPbBr3 heterojunction.
Hyunmin Lee1, Sangeun Baek1, Jinwoo Choi1
1Department of Chemistry, Hanyang University, Seoul 04763, Republic of Korea. youngjkang@hanyang.ac.kr.
Materials Horizons
|June 16, 2026
Summary
Chemical transformation of 0D Cs4PbBr6 crystals creates a 3D CsPbBr3 surface layer, enabling distinct electronic and ionic transport for novel iontronic devices.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Device Physics
Background:
- Lead halide perovskites are crucial for next-generation iontronics due to their coupled electronic and ionic transport.
- Controlling ion transport in these materials is key to developing advanced devices.
Purpose of the Study:
- To investigate the impact of surface chemical modification on charge transport dynamics in lead halide perovskites.
- To engineer a heterojunction with polarity-dependent behavior for iontronic applications.
Main Methods:
- Post-synthetic chemical transformation of 0D Cs4PbBr6 single crystals to a 3D CsPbBr3-rich surface layer using Prussian blue treatment.
- Temporal response measurements to analyze charge transport dynamics.
- Construction and characterization of a monolithic Cs4PbBr6/CsPbBr3 heterojunction.
Main Results:
- The transformation created a CsPbBr3-rich surface with facile ion migration via Pb-Br-Pb pathways, contrasting with the pristine 0D crystal's restricted ionic activity.
- The Cs4PbBr6/CsPbBr3 heterojunction exhibited polarity-dependent transient responses, mimicking memristive-diode behavior.
- Asymmetric carrier injection at the interface, specifically electron accumulation under reverse bias, suppressed ionic migration by neutralizing bromide vacancies.
Conclusions:
- Chemically engineering perovskite heterostructures can create distinct transport properties.
- This work provides mechanistic insights into ion gating in mixed conductors.
- A materials-level design principle for electronically controlling ionic defects in perovskites was demonstrated.
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