# Letian Dou
**Letian Dou** (Dou, Letian) is a materials chemist and chemical engineer who studies hybrid organic–inorganic semiconductor materials, including organic semiconductor-incorporated perovskites (OSiPs), organic solar cells, and optoelectronic devices. He is the Paul & Phyllis Fireman Professor of Chemistry at [Emory University](https://www.edgepedia.org/emory-university), a position he has held since 2025, and before that was Charles Davidson Associate Professor of Chemical Engineering, with a courtesy appointment in Chemistry, at [Purdue University](https://www.edgepedia.org/purdue-university) from 2017 to 2025.[1](https://letiandougroup.com/about/) His laboratory defines and develops OSiP materials and applies them in solar cells, light-emitting diodes, transistors, and related devices.[2](https://www.chem.purdue.edu/people/profile/dou10)
| Key fact | Detail |
|---|---|
| Current position | Paul & Phyllis Fireman Professor of Chemistry, Emory University, since 2025[1](https://letiandougroup.com/about/) |
| Previous position | Charles Davidson Associate Professor of Chemical Engineering (Chemistry by courtesy), Purdue University, 2017–2025[1](https://letiandougroup.com/about/) |
| Training | B.S. Chemistry, Peking University, 2009; Ph.D. Materials Science and Engineering, UCLA, 2014; postdoc, UC Berkeley and Lawrence Berkeley National Laboratory, 2014–2017[1](https://letiandougroup.com/about/) |
| Signature work | 2015 *Science* paper on atomically thin two-dimensional organic–inorganic hybrid perovskites[3](https://engineering.purdue.edu/ChE/people/ptProfile?resource_id=169342); ["Two-dimensional halide perovskite lateral epitaxial heterostructures"](https://doi.org/10.1038/s41586-020-2219-7), *Nature*, 2020 |
| Known for | Defining OSiP (organic semiconductor-incorporated perovskite) hybrid materials and epitaxial halide perovskite heterostructures[2](https://www.chem.purdue.edu/people/profile/dou10) |
| Major honors | NSF CAREER (2021), ONR Young Investigator (2019), Humboldt Research Fellowship (2024), ACS Photonics Young Investigator Lectureship (2025)[4](https://www.humboldt-foundation.de/en/connect/explore-the-humboldt-network/singleview/1237958/prof-dr-letian-dou) • [5](https://engineering.buffalo.edu/chemical-biological/news-events/events/seminar-series/spring-2025-seminar-series0/letian-dou.html) |
## Education and career
Dou received his B.S. in Chemistry from [Peking University](https://www.edgepedia.org/peking-university) in 2009.[1](https://letiandougroup.com/about/) He then joined [Yang Yang](https://www.edgepedia.org/yang-yang)'s group in the Department of Materials Science and Engineering at UCLA and obtained his Ph.D. in 2014, co-advised by [Fred Wudl](https://www.edgepedia.org/fred-wudl) at UC Santa Barbara during 2013; his doctoral research focused on conjugated polymers for organic and hybrid photovoltaic applications.[1](https://letiandougroup.com/about/) • [6](https://mse.osu.edu/events/2017/04/mse-colloquium-letian-dou-solution-processed-semiconducting-polymers-and) From 2014 to 2017 he was a postdoctoral fellow with Peidong Yang in UC Berkeley's Department of Chemistry and the Materials Science Division of Lawrence Berkeley National Laboratory.[1](https://letiandougroup.com/about/)
According to the Humboldt Foundation, in 2025 he moved to Emory University in Atlanta as Paul & Phyllis Fireman Professor of Chemistry; the Humboldt Foundation lists him at Emory University's Department of Chemistry.[4](https://www.humboldt-foundation.de/en/connect/explore-the-humboldt-network/singleview/1237958/prof-dr-letian-dou) He became an associate editor for *Science Advances* and joined the Early Career Board of *ACS Photonics*.[1](https://letiandougroup.com/about/)
## Research program: OSiP and hybrid semiconductors
Dou's group defines organic semiconductor-incorporated perovskites (OSiPs) as a sub-class of two-dimensional halide perovskites that combine the electronic functionality of organic semiconductors with the soft, dynamic halide perovskite lattice.[2](https://www.chem.purdue.edu/people/profile/dou10) • [7](https://doi.org/10.1021/jacs.3c02143) Because the organic and inorganic layers meet at an atomically flat interface with an ultra-small interlayer distance, energy transfer and charge transfer between adjacent layers are extremely fast and efficient.[5](https://engineering.buffalo.edu/chemical-biological/news-events/events/seminar-series/spring-2025-seminar-series0/letian-dou.html) This combination lets researchers tailor the energy landscape, lattice and carrier dynamics, and electron and ion transport, with applications in photovoltaics, light-emitting devices, and transistors.[7](https://doi.org/10.1021/jacs.3c02143) Active group projects span two-dimensional OSiP chemistry and physics, perovskite- and OSiP-based solar cells, LEDs, transistors, thermoelectric, and memory devices, and bioelectronics using intrinsically stretchable materials.[2](https://www.chem.purdue.edu/people/profile/dou10)
## Representative work
His 2015 *Science* paper "Atomically Thin Two-dimensional Organic-inorganic Hybrid Perovskites" (Science 349, 1518–1521) demonstrated perovskite structures reduced to atomic thickness, establishing the hybrid 2D materials family his group has developed since.[3](https://engineering.purdue.edu/ChE/people/ptProfile?resource_id=169342) In a later milestone, his group demonstrated for the first time an epitaxial halide perovskite heterostructure with a near atomically sharp interface, something that high intrinsic ion mobility and poor chemical stability had previously prevented.[5](https://engineering.buffalo.edu/chemical-biological/news-events/events/seminar-series/spring-2025-seminar-series0/letian-dou.html)
Between these, a 2023 *Nature Chemistry* paper reported a general solvent-choice method to tune the dimensionality of phase-pure OSiP single crystals during synthesis; longer and more planar π-conjugated organic cations induced a more rigid inorganic lattice, suppressing exciton–phonon interactions and enabling lasing with substantially lower thresholds than conventional 2D perovskites.[8](https://www.nature.com/articles/s41557-023-01311-0) In 2024 the group presented a strategy to substantially inhibit in-plane ion diffusion in 2D halide perovskites by incorporating rigid π-conjugated organic ligands, enabling stable and tunable lateral and vertical epitaxial heterostructures, multiheterostructures, and superlattices.[9](https://google.iopscience.iop.org/article/10.1149/MA2024-01121001mtgabs)
In January 2026 the group's paper "Mosaic lateral heterostructures in two-dimensional perovskite" was published in *Nature*.[11](https://letiandougroup.com/2026/01/19/)
## How hybrid perovskites compare with other approaches
Low-dimensional perovskites show greater phase stability and superior ambient, light, and thermal stability compared with 3D perovskites, whose poor stability limits practical use.[12](https://preview-www.nature.com/articles/s41578-025-00847-6) • [13](https://www.nanoge.org/proceedings/PerFunPro/684b1b41b0a44a1272a46c17) 2D/3D heterojunctions have enabled many solar cell devices with greater than 25% power conversion efficiency; a *Science* paper reported 25.9% efficiency with 91% retention after 1,074 hours at 85°C under maximum power point tracking, and a 2025 *Nature Communications* paper reported 26.05% (certified 25.44%) with 82% retention after 1,000 hours of damp-heat testing.[14](https://pubs.rsc.org/en/content/articlelanding/2024/cc/d4cc02299h) • [15](https://www.science.org/doi/10.1126/science.adr1334) • [16](https://www.nature.com/articles/s41467-025-56409-5) By comparison, Dou's earlier team set a certified world record of 10.6% power conversion efficiency for pure organic solar cells.[3](https://engineering.purdue.edu/ChE/people/ptProfile?resource_id=169342)
The control point is ligand design. A *Nature Reviews Materials* review identifies the monovalent ammonium ligands commonly used in 3D/low-dimensional heterojunctions as relatively unstable owing to weak van der Waals interactions and low pKa, and recommends multivalent amines with high pKa values.[12](https://preview-www.nature.com/articles/s41578-025-00847-6) Dou's rigid conjugated ligand design addresses this directly, enhancing chemical stability, suppressing solid-state ion diffusion, and modulating electron–phonon coupling; his group has demonstrated efficient light emission and amplification in single-crystalline nanostructures, epitaxial heterostructures, and polycrystalline thin films, targeting solid-state lighting.[13](https://www.nanoge.org/proceedings/PerFunPro/684b1b41b0a44a1272a46c17)
## References
1. About the PI – Letian Dou Group. https://letiandougroup.com/about/
2. Letian Dou – Department of Chemistry, Purdue University. https://www.chem.purdue.edu/people/profile/dou10
3. Letian Dou – Davidson School of Chemical Engineering, Purdue University. https://engineering.purdue.edu/ChE/people/ptProfile?resource_id=169342
4. Prof. Dr. Letian Dou – Alexander von Humboldt Foundation. https://www.humboldt-foundation.de/en/connect/explore-the-humboldt-network/singleview/1237958/prof-dr-letian-dou
5. Letian Dou – University at Buffalo seminar abstract. https://engineering.buffalo.edu/chemical-biological/news-events/events/seminar-series/spring-2025-seminar-series0/letian-dou.html
6. MSE Colloquium: Letian Dou – The Ohio State University. https://mse.osu.edu/events/2017/04/mse-colloquium-letian-dou-solution-processed-semiconducting-polymers-and
7. Emerging Two-Dimensional Organic Semiconductor-Incorporated Perovskites (JACS). https://doi.org/10.1021/jacs.3c02143
8. Thickness control of organic semiconductor-incorporated perovskites (Nature Chemistry, 2023). https://www.nature.com/articles/s41557-023-01311-0
9. (Invited) Two-Dimensional Organic-Perovskite Hybrid Materials and Heterostructures (ECS Meeting Abstracts, 2024). https://google.iopscience.iop.org/article/10.1149/MA2024-01121001mtgabs
10. Letian Dou @ Purdue (@DouLetian) archive. https://vanlett.com/DouLetian
11. January 19, 2026 – Letian Dou Group. https://letiandougroup.com/2026/01/19/
12. Dimensionality engineering of perovskites for stable heterojunction-based photovoltaics | Nature Reviews Materials. https://preview-www.nature.com/articles/s41578-025-00847-6
13. Light Emission and Lasing in OSiP – nanoGe PerFunPro. https://www.nanoge.org/proceedings/PerFunPro/684b1b41b0a44a1272a46c17
14. Advances and challenges in molecular engineering of 2D/3D perovskite heterostructures – Chemical Communications. https://pubs.rsc.org/en/content/articlelanding/2024/cc/d4cc02299h
15. Spontaneous formation of robust two-dimensional perovskite phases | Science. https://www.science.org/doi/10.1126/science.adr1334
16. Solvent-dripping modulated 3D/2D heterostructures for high-performance perovskite solar cells | Nature Communications. https://www.nature.com/articles/s41467-025-56409-5
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*Topic: Encyclopedia › Physical world and mathematics › Physical and mathematical scientists › Chemists › Researchers in polymer, supramolecular, and materials chemistry › Conjugated and organic electronic materials*
*Initially written Sep 20, 2026 · Reviewed: Sep 25, 2026 · Edited: Sep 25, 2026; Oct 11, 2026 · Last review: Sep 25, 2026*
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