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Chinese Journal of Chemistry 2022年第5期40卷 597-602页

作者： Jianqiao Wang Huanhuan Zhang yuguang ma State Key Laboratory of Luminescent materials and Devices Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyNo.381 Wushan RoadTianhe DistinctGuangzhouGuangdong510640 China

Doping plays an essential role in the properties of conducting polymers.Film thickness not only has a direct influence on their photoelectric properties,but also affects the doping ability,which may lead to the decline of capacitance and electrochromic properties caused by incomplete doping.Therefore,it is essential to study the quantitative relationship between doping level and film thickness in application.Herein,empirical formula between doping level and thickness was obtained by studying the spectroelectrochemistry behaviors of two different electrochromic materials,poly(N,N'-bis(3,5-(2-thienyl)-phenyl)-1,6,7,12-tetrachloroperylene-3,4,9,10-perylenetetracarboxylic diimide)(poly(Th-Cl-PBI))and poly(3,4-ethylenedioxythiophene)(PEDOT).The doping level is verified to be correlated to the reciprocal of the 3^(rd)power of film thickness.Experimental results fit these formulas very well,giving correlation coefficient R^(2)higher than 0.99.The optical contrast prediction of these two electrochromic materials is also used to verify this relationship formula.For the first time,we quantitatively connect these two important parameters of conducting polymers,doping level and thickness.

关键词： Doping Electrochemistry Polymers Electrochromism Thickness dependence

A Cathodic Electrochromic material Based on Thick Perylene Bisimide Film with High Optical Contrast and High Stability

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CCS Chemistry 2022年第4期4卷 1347-1356页

作者： Jianqiao Wang Weitao ma Hailong Wang Zengqi Xie Huanhuan Zhang yuguang ma State Key Laboratory of Luminescent materials and Devices Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyTianhe DistrictGuangzhou 510640

Cathodic electrochromic materials realized by n-type doping of conducting polymers are scarce.Even with limited cases reported in the literature,long-term stability is an urgent problem to be solved.Herein,we report a high performance and stable cathodic electrochromic material,poly(Th-Cl-PBI),based on a perylene bisimide function core.Due to its high electropolymerization efficiency and low steric hindrance of thiophene groups,perylene bisimide,which generally does not dissolve and form film easily,can grow to the sufficient thickness of 350 nm for wide-range spectral modulation and large-capacity energy storage.The optical contrast of optimized film with a thickness of 240 nm reaches as high as 69.1% at 520 nm,94.1% at 760 nm,and 95.7% at 680 nm.Theoretical simulation based on the Lambert–Beer law also verifies this optical contrast dependent on film thickness.Besides,during the transition between the neutral state and radical anion state,it maintains 90.2% of the electrochemical activity after 4000 cycles,and the transmittance spectrum remains stable after 2000 cycles.The cation size effect on cathodic electrochromic process and cyclic stability has been investigated.

关键词： cathodic electrochromism perylene bisimide n-type doping film thickness optical contrast stability

Utilizing morpholine for purely organic room temperature phosphors

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Science China Chemistry 2023年第4期66卷 1132-1138页

作者： Dongyan Jiang Tong Lu Chunya Du Futong Liu Zhenyu Yan Dehua Hu Anqi Shang Lei Gao Ping Lu yuguang ma State Key Laboratory of Supramolecular Structure and materials Department of ChemistryJilin UniversityChangchun 130012China Institute of Polymer Optoelectronic materials and Devices State Key Laboratory of Luminescent Materials and DevicesSouth China University of TechnologyGuangzhou 510640China

In this article,morpholine,a non-conjugated heterocycle,is embedded intoπsystem to construct single-component organic room temperature phosphorescence(RTP)luminogens.The effect of morpholine on intermolecular interaction,crystal packing modes,and RTP performance is investigated systematically.The experimental and theoretical calculation results illustrate the versatility of morpholine in promoting the n-π*transition and intensifying the intermolecular interactions,which not only enhances the generation of triplet excitons,but also suppresses the nonradiative decay of triplet excitons.Impressively,TMPh containing three morpholine units shows an ultralong lifetime of 1.03 s and a visible afterglow up to 10 s.The unique dual delayed emission and long afterglow property allow potential application of morpholine derivatives in data encryption,and the time-dependent color change of afterglow emission is realized after removing the excitation source,providing a high-level data security.This article provides a new perspective for the design of purely organic RTP system without utilization of metal,or even any heavy atoms.

关键词： morpholine room temperature phosphorescence aggregation noncovalent interactions thermally activated delayed fluorescence

Organic single-crystal light-emitting transistors with external quantum efficiency over 20%

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聚集体(英文) 2023年第4期4卷 122-127页

作者： Jian Deng Zejian Zhang Pengpeng Sang Shujun Yin Shitong Zhang Yuan Li Bing Yang Cheng Gu yuguang ma State Key Laboratory of Luminescent materials and Devices Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhouP.R.China School of Information Science and Engineering Shandong UniversityQingdaoP.R.China State Key Laboratory of Supramolecular Structure and materials Institute of Theoretical ChemistryCollege of ChemistryJilin UniversityChangchunP.R.China Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of TechnologyGuangzhouP.R.China

Organic light-emitting transistors(OLETs)have attracted increasing attention because of their potential applications in next-generation displays and high-energy operating devices.However,the simultaneous achievement of high luminescent efficiency and carrier mobility in organic semiconductors remains challenging because the localized excitons are advantageous for light emission,whereas the delocalized carriers are beneficial for efficient charge migration.Herein,we report an organic single crystal of a cyano-substituted styrene derivative with balanced mobility yielding a record-high external quantum efficiency of 20.5%in OLETs.Temperature-dependent I–V curves and electronic structure analyses based on firstprinciples calculations were performed to disclose the underlying mechanism as a band transport,which provides an efficient way to achieve high quantum efficiency in OLETs.

关键词： organic electronics organic light-emitting transistors single crystals styrene

Violating the Aufbau principle: an efficient way to improve the stability of luminescent radicals

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Science China Chemistry 2019年第12期62卷 1551-1552页

作者： yuguang ma Institute of Polymer Optoelectronic materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology

The Aufbau principle,also known as“building-up”principle,is a method of explaining the arrangements of electrons within atoms of different chemical elements.The principle was initially introduced by Danish physicist Niels Bohr and the basic statements include“Electrons will fill orbitals in increasing order of energy,and each orbital can contain a maximum of two electrons,and these must have opposite spins”[1].The principle is not perfect,and there are a few exceptions,but it is a very useful tool for learning about atomic and molecular structure.

关键词： structure. stability arrangement

Progress in small-molecule luminescent materials for organic light-emitting diodes

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Science China Chemistry 2015年第6期58卷 907-915页

作者： Tiancheng Yu Linlin Liu Zengqi Xie yuguang ma State Key Laboratory of Luminescent materials and Devices Institute of Polymer Optoelectronic materials and Devices South China University of Technology

Organic light-emitting diodes(OLEDs) have been extensively studied since the first efficient device based on small molecular luminescent materials was reported by Tang. Organic electroluminescent material, one of the centerpieces of OLEDs, has been the focus of studies by many material scientists. To obtain high luminosity and to keep material costs low, a few remarkable design concepts have been developed. Aggregation-induced emission(AIE) materials were invented to overcome the common fluorescence-quenching problem, and cross-dipole stacking of fluorescent molecules was shown to be an effective method to get high solid-state luminescence. To exceed the limit of internal quantum efficiency of conventional fluorescent materials, phosphorescent materials were successfully applied in highly efficient electroluminescent devices. Most recently, delayed fluorescent materials via reverse-intersystem crossing(RISC) from triplet to singlet and the "hot exciton" materials based on hybridized local and charge-transfer(HLCT) states were developed to be a new generation of low-cost luminescent materials as efficient as phosphorescent materials. In terms of the device-fabrication process, solution-processible small molecular luminescent materials possess the advantages of high purity(vs. polymers) and low procession cost(vs. vacuum deposition), which are garnering them increasing attention. Herein, we review the progress of the development of small-molecule luminescent materials with different design concepts and features, and also briefly examine future development tendencies of luminescent materials.

关键词：电致发光材料有机发光二极管小分子电致发光器件 OLED 中心焦点磷光材料材料科学家

Highly Efficient Blue Organic Light-Emitting Diode Based on a Pyrene[4,5-d]Imidazole-Pyrene Molecule

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CCS Chemistry 2022年第1期4卷 214-227页

作者： Yulong Liu Xiaxia man Qing Bai Hui Liu Pengyuan Liu Ying Fu Dehua Hu Ping Lu yuguang ma State Key Laboratory of Supramolecular Structure and materials Department of ChemistryJilin UniversityChangchun 130012 Department of Chemistry College of Arts and SciencesNortheast Agricultural UniversityHarbin 150030 The First Hospital of Jilin University Changchun 130021 Institute of Polymer Optoelectronic materials and Devices State Key Laboratory of Luminescent Materials and DevicesSouth China University of TechnologyGuangzhou 510640

Organic light-emitting diodes(OLEDs),which have been recently utilized in some flat-panel display screens such as mobile phones and televisions,show many merits,including light weight,high flexibility,energy preservation,and so forth,and are considered the next-generation displays and solid-state lightings.Blue-emitting materials that can be applied in nondoped OLEDs with little efficiency roll-offs at high brightness are of great importance.Here,a highly efficient,blue-emitting material,9-phenyl10-(4-(pyren-1-yl)phenyl)-9H-pyreno[4,5-d]imidazole(PyPI-Py),is achieved using pyrene[4,5-d]imidazole and pyrene as the weak electron donor and electron acceptor,respectively.The nondoped blue OLED exhibits excellent performance with a maximum brightness of 75,687 cd m^(−2),a maximum current efficiency of 13.38 cd A−1,and a maximum external quantum efficiency(ηext)of 8.52%.Moreover,theηext is maintained at 8.35%and 8.05%at a brightness of 10,000 and 50,000 cd m^(−2),respectively,displaying extremely small efficiency roll-offs of 2.0%and 5.5%.The device characteristics are among the highest values for nondoped blue OLEDs and correspond to the best performance obtained for nondoped pyrene-based blue OLEDs.The superior performance is attributed to the proper donor–acceptor design strategy which results in a quasi-equivalent hybrid local and charge-transfer excited state with the maximum generation of an 82%fraction of singlet excitons.

关键词： pyrene imidazole nondoped OLEDs blue emission efficiency roll-off

Precursor synthesis strategy for polycyclic aromatic conjugated polymers on the application of supercapacitors

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Science China Chemistry 2018年第2期61卷 192-199页

作者： Zhenhua Zhang Weitao ma Biao Xu Xuehong Zhou Cong Wang Zengqi Xie Linlin Liu yuguang ma Institute of Polymer Optoelectronic materials and Devices State Key Laboratory of Luminescent Materials and DevicesSouth China University of Technology

Polycyclic aromatics (PCAs) possess excellent photoelectric properties, but the construction of such compounds has been a quite challenging subject of study, mainly due to very low solubility. Herein we report a precursor synthesis strategy for polycyclic aromatic conjugated polymers. A soluble precursor polymer, that containing fusible "double U-shaped aromatic"(DUA) and perylenetetracarboxydiimide (PDI) units, was firstly synthesized by Suzuki coupling. The stereo aromatic units in polymer backbone were found to be converted into polycyclic aromatic units, i.e. hexa-peri-hexabenzocoronene (HBC), by chemical or electrochemical oxidation, which resulted in a formation of insoluble polycyclic aromatic conjugated polymers. The electrochemical oxidations that occurred at the interface of electrode and solution exhibited higher cyclization reactivity and leads to the formation of high quality films on the electrode surface. Characterization by Raman and UV-visible (UV-Vis) spectroscopy validated the successful formation of this HBC structure. Some potential applications of such thin films are being explored, and here we focus on the characteristics of supercapacitors based on their excellent electrochemical properties.

关键词：应用程序聚合物芳香合成电气化学电极表面环合反应紫外可见

Preparation and electronic characteristics of anionic perylene bisimide films

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Science China Chemistry 2017年第10期60卷 1334-1339页

作者： Wenqiang Zhang Qinglin Jiang Jiadong Zhou Dehua Hu Xuehong Zhou Weitao ma Muddasir Hanif Zengqi Xie Linlin Liu yuguang ma State Key Laboratory of Supramolecular Structure and materials Jilin University Institute of Polymer Optoelectronic materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology

Neutral perylene bisimides(PBI) are well-known n-type organic semiconductors, with number of challenging electronic properties in their neutral and reduced states. We report the characteristic electronic properties of PBI anionic films. We unexpectedly discovered that pristine PBI dianion film showed p-type character, while oxidized dianion film(dominant neutral state with few radical anions) showed normal n-type semiconductor character based on Seebeck effect measurements. Both kinds of films exhibit high electrical conductivity with a potential for thermoelectric applications. The mechanism of polarity reversal is proposed.

关键词：阴离子膜电学特性苝酰亚胺薄膜有机半导体材料制备塞贝克效应半导体特性

The effect of interfacial diffusion on device performance of polymer solar cells: a quantitative view by active-layer doping

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Science China Chemistry 2015年第2期58卷 317-322页

作者： Li Nian Jiadong Zhou Kai Zeng Xiaoyan Wu Linlin Liu Zengqi Xie Fei Huang yuguang ma Institute of Polymer Optoelectronic materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology

The diffusion of constituent materials at interfaces is one of the key factors for device performance and stability.In this work,the effect of interfacial diffusion of a classic interfacial material PFN on device performance of polymer solar cells was studied quantitatively by doping PFN into active layer based on P3HT:PC61BM blend.The PCEs of devices with 550 ppm PFN decrease to half compared to those of the control devices without PFN,which are mainly attributed to the decrease of short-circuit current(Jsc)and fill factor(FF).Advanced analyses of equivalent circuit,absorption spectra,and atomic force microscopy indicates that the presence of PFN in the active layer increases the leakage current,decreases the aggregation of P3HT,and reduces the phase separation.This research reveals the physical mechanism of interfacial diffusion in device performance and provides a basis for further improving the performance and stability of PSCs.

关键词：界面扩散太阳能电池聚合物过掺杂性能器件有源层视图