@article{dong_fu_seyitliyev_darabi_mendes_lei_chen_chang_amassian_gundogdu_et al._2022, title={Cavity Engineering of Perovskite Distributed Feedback Lasers}, volume={9}, ISSN={2330-4022 2330-4022}, url={http://dx.doi.org/10.1021/acsphotonics.2c00917}, DOI={10.1021/acsphotonics.2c00917}, number={9}, journal={ACS Photonics}, publisher={American Chemical Society (ACS)}, author={Dong, Qi and Fu, Xiangyu and Seyitliyev, Dovletgeldi and Darabi, Kasra and Mendes, Juliana and Lei, Lei and Chen, Yi-An and Chang, Chih-Hao and Amassian, Aram and Gundogdu, Kenan and et al.}, year={2022}, month={Aug}, pages={3124–3133} }
 @article{biliroglu_findik_mendes_seyitliyev_lei_dong_mehta_temnov_so_gundogdu_2022, title={Room-temperature superfluorescence in hybrid perovskites and its origins}, volume={16}, ISSN={["1749-4893"]}, url={https://doi.org/10.1038/s41566-022-00974-4}, DOI={10.1038/s41566-022-00974-4}, number={4}, journal={NATURE PHOTONICS}, publisher={Springer Science and Business Media LLC}, author={Biliroglu, Melike and Findik, Gamze and Mendes, Juliana and Seyitliyev, Dovletgeldi and Lei, Lei and Dong, Qi and Mehta, Yash and Temnov, Vasily V. and So, Franky and Gundogdu, Kenan}, year={2022}, month={Apr}, pages={324-+} }
 @article{fu_mehta_chen_lei_zhu_barange_dong_yin_mendes_he_et al._2021, title={Directional Polarized Light Emission from Thin‐Film Light‐Emitting Diodes}, volume={33}, ISSN={0935-9648 1521-4095}, url={http://dx.doi.org/10.1002/adma.202006801}, DOI={10.1002/adma.202006801}, abstractNote={Abstract}, number={9}, journal={Advanced Materials}, publisher={Wiley}, author={Fu, Xiangyu and Mehta, Yash and Chen, Yi‐An and Lei, Lei and Zhu, Liping and Barange, Nilesh and Dong, Qi and Yin, Shichen and Mendes, Juliana and He, Siliang and et al.}, year={2021}, month={Jan}, pages={2006801} }
 @article{findik_biliroglu_seyitliyev_mendes_barrette_ardekani_lei_dong_so_gundogdu_2021, title={High-temperature superfluorescence in methyl ammonium lead iodide}, volume={15}, ISSN={1749-4885 1749-4893}, url={http://dx.doi.org/10.1038/s41566-021-00830-x}, DOI={10.1038/s41566-021-00830-x}, abstractNote={Light–matter interactions can create and manipulate collective many-body phases in solids1–3, which are promising for the realization of emerging quantum applications. However, in most cases, these collective quantum states are fragile, with a short decoherence and dephasing time, limiting their existence to precision tailored structures under delicate conditions such as cryogenic temperatures and/or high magnetic fields. In this work, we discovered that the archetypal hybrid perovskite, MAPbI3 thin film, exhibits such a collective coherent quantum many-body phase, namely superfluorescence, at 78 K and above. Pulsed laser excitation first creates a population of high-energy electron–hole pairs, which quickly relax to lower energy domains and then develop a macroscopic quantum coherence through spontaneous synchronization. The excitation fluence dependence of the spectroscopic features and the population kinetics in such films unambiguously confirm all the well-known characteristics of superfluorescence. These results show that the creation and manipulation of collective coherent states in hybrid perovskites can be used as the basic building blocks for quantum applications4,5. A collective coherent quantum many-body phase, namely superfluorescence, is observed in CH3NH3PbI3 at 78 K. The excitation fluence dependence of the spectroscopic features and the population kinetics confirm all its well-known characteristics.}, number={9}, journal={Nature Photonics}, publisher={Springer Science and Business Media LLC}, author={Findik, Gamze and Biliroglu, Melike and Seyitliyev, Dovletgeldi and Mendes, Juliana and Barrette, Andrew and Ardekani, Hossein and Lei, Lei and Dong, Qi and So, Franky and Gundogdu, Kenan}, year={2021}, month={Jun}, pages={676–680} }
 @article{fu_yin_chen_zhu_dong_chang_so_2021, title={Light extraction in tandem organic light emitting diodes}, volume={119}, ISSN={["1077-3118"]}, url={https://doi.org/10.1063/5.0057325}, DOI={10.1063/5.0057325}, abstractNote={Since the invention of organic light emitting diodes (OLEDs), great research efforts have been dedicated to improving their efficiency and lifetime. For high-brightness applications, tandem OLED structures have advantages because of the lower current densities required to achieve high brightness. With the successful development of highly efficient charge generation layers, high brightness tandem OLEDs are used in displays and lighting. However, the major challenge for tandem OLEDs is the low light extraction efficiency, because about 50% of the light is trapped inside the device as waveguide modes. In this Perspective, we first review the recent works done on light extraction, analyze different waveguide mode extraction structures, and then identify the key factors determining the extraction efficiencies in tandem OLEDs.}, number={6}, journal={APPLIED PHYSICS LETTERS}, author={Fu, Xiangyu and Yin, Shichen and Chen, Yi-An and Zhu, Liping and Dong, Qi and Chang, Chih-Hao and So, Franky}, year={2021}, month={Aug} }
 @misc{lei_dong_gundogdu_so_2021, title={Metal Halide Perovskites for Laser Applications}, volume={31}, ISSN={["1616-3028"]}, DOI={10.1002/adfm.202010144}, abstractNote={Abstract}, number={16}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Lei, Lei and Dong, Qi and Gundogdu, Kenan and So, Franky}, year={2021}, month={Apr} }
 @article{lei_seyitliyev_stuard_mendes_dong_fu_chen_he_yi_zhu_et al._2020, title={Efficient Energy Funneling in Quasi-2D Perovskites: From Light Emission to Lasing}, volume={32}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201906571}, abstractNote={Abstract}, number={16}, journal={ADVANCED MATERIALS}, author={Lei, Lei and Seyitliyev, Dovletgeldi and Stuard, Samuel and Mendes, Juliana and Dong, Qi and Fu, Xiangyu and Chen, Yi-An and He, Siliang and Yi, Xueping and Zhu, Liping and et al.}, year={2020}, month={Apr} }
 @article{ho_kim_xiong_firdaus_yi_dong_rech_gadisa_booth_brendan t. o'connor_et al._2020, title={High-Performance Tandem Organic Solar Cells Using HSolar as the Interconnecting Layer}, volume={10}, ISSN={["1614-6840"]}, url={https://doi.org/10.1002/aenm.202000823}, DOI={10.1002/aenm.202000823}, abstractNote={Abstract}, number={25}, journal={ADVANCED ENERGY MATERIALS}, publisher={Wiley}, author={Ho, Carr Hoi Yi and Kim, Taesoo and Xiong, Yuan and Firdaus, Yuliar and Yi, Xueping and Dong, Qi and Rech, Jeromy J. and Gadisa, Abay and Booth, Ronald and Brendan T. O'Connor and et al.}, year={2020}, month={Jul} }
 @misc{dong_lei_mendes_so_2020, title={Operational stability of perovskite light emitting diodes}, volume={3}, ISSN={["2515-7639"]}, DOI={10.1088/2515-7639/ab60c4}, abstractNote={Abstract}, number={1}, journal={JOURNAL OF PHYSICS-MATERIALS}, author={Dong, Qi and Lei, Lei and Mendes, Juliana and So, Franky}, year={2020}, month={Jan} }
 @article{dong_mendes_lei_seyitliyev_zhu_he_gundogdu_so_2020, title={Understanding the Role of Ion Migration in the Operation of Perovskite Light-Emitting Diodes by Transient Measurements}, volume={12}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.0c14269}, abstractNote={Perovskite light-emitting diodes have been gaining attention in recent years due to their high efficiencies. Despite of the recent progress made in device efficiency, the operation mechanisms of these devices are still not well understood, especially the effects of ion migration. In this work, the role of ion migration is investigated by measuring the transient electroluminescence and current responses, with both the current and efficiency showing a slow response in a time scale of tens of milliseconds. The results of the charge injection dynamics show that the slow response of the current is attributed to the migration and accumulation of halide ions at the anode interface, facilitating hole injection and leading to a strong charge imbalance. Further, the results of the charge recombination dynamics show that the slow response of the efficiency is attributed to enhanced charge injection facilitated by ion migration, which leads to an increased carrier density favoring bimolecular radiative recombination. Through a combined analysis of both charge injection and recombination dynamics, we finally present a comprehensive picture of the role of ion migration in device operation.}, number={43}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Dong, Qi and Mendes, Juliana and Lei, Lei and Seyitliyev, Dovletgeldi and Zhu, Liping and He, Siliang and Gundogdu, Kenan and So, Franky}, year={2020}, month={Oct}, pages={48845–48853} }
 @article{dong_ho_yu_salehi_so_2019, title={Defect Passivation by Fullerene Derivative in Perovskite Solar Cells with Aluminum-Doped Zinc Oxide as Electron Transporting Layer}, volume={31}, ISSN={["1520-5002"]}, DOI={10.1021/acs.chemmater.9b01292}, abstractNote={ZnO is a potential replacement for TiO2 as an electron transport layer (ETL) used in low-temperature processed hybrid perovskite solar cells. However, poor thermal stability of perovskites on ZnO and interfacial traps introduced during processing are obstacles to achieve a good device performance. Here, we demonstrate perovskite solar cells using aluminum doped zinc oxide (AZO) nanoparticles for the ETL having a better thermal stability compared with ZnO. However, the device shows a lower short circuit current density and a large photocurrent hysteresis, which are attributed to the poor interfacial properties between the ETL and the perovskite layer. To address this issue, a thin interfacial modification layer of phenyl-C61-butyric acid methyl ester (PCBM) was employed. The resulting device shows the efficiency is improved from 13 to 17% along with a significant reduction in hysteresis. Results from our thermal admittance spectroscopy show that the interface defect states are significantly reduced with th...}, number={17}, journal={CHEMISTRY OF MATERIALS}, author={Dong, Qi and Ho, Carr Hoi Yi and Yu, Hyeonggeun and Salehi, Amin and So, Franky}, year={2019}, month={Sep}, pages={6833–6840} }