Integrating photonics and electronics into a single chip with a variety of capabilities is attracting particular interest for achieving high-density and highspeed multifunctional smart optoelectronic systems. However, it remains challenging to realize this goal because of the difficulty of merging various areas of science and technology. A smart responsive integrated photoelectric organic modulator is created here, which can not only possess emission wavelength switching tunability in response to light and heat but also show good optical amplification performance and field-effect transistor properties. By applying external stimuli on the resulting smart responsive system based on the judicious combination of conjugated polymers and photochromic molecules can enable efficient and reversible tuning of light emission between red and yellow via a controllable way through effective manipulation of energy transfer channels induced by optical and thermal stimuli. More importantly, stimuli-responsive emission, optical amplification, and efficient carrier transport can be simultaneously integrated in a single device with optical and electrical performance comparable to those of stand-alone devices. The results suggest an effective way to create smart integration of photonic and electronic elements in a chip with multifunctional optoelectronic characteristics for various applications such as integrated photonics, electronics, optoelectronics, and smart sensing.

In recent years, conjugated starburst molecules, which possess a core unit with radial arms linked to the central axle, have become the research topic owing to their well-defined chemical structures, good solution processability, excellent reproducibility, and superior optoelectronic properties. The increasing interest in starburst systems is evidenced by progressively more frequent investigation on the use of these materials in optoelectronics. The ability to modify chemical structures through control over the core and arms on a molecular level can directly affect the electronic and electroluminescent characteristics of the resulting materials. In this review, we summarize and discuss main progress in our group concerning the rapidly developing field, in which strategies for the design and construction of starbursts are presented at length. Moreover, their application in organic light-emitting diodes (OLEDs) and organic semiconductor lasers (OSLs) are demonstrated as well, exploring the influence of molecular structures on the optoelectronic properties. Challenges and outlooks are also given at last.

Herein, the photophysical, morphological, optical gain characteristics of a set of trigonal monodisperse starburst conjugated macromolecules (Tr1‐Tr4) have been systematically investigated in order to elucidate the influence of the molecular structures on their optoelectronic performance. With increasing the oligofluorene arm length, absorption spectra were red‐shifted progressively, whereas an increase in photoluminescence quantum yields (PLQYs) and optical gain coefficients, and a corresponding reduction in amplified spontaneous emission (ASE) thresholds and loss coefficients were observed for Tr1‐Tr3 except for Tr4. The results indicate that the effective conjugation length become saturated for Tr3 in this system. Impressively, the resulting molecules manifested very low ASE thresholds (4.4–11.6 μJ cm−2) with high photostability, as well as high thermal stability. One dimensional distributed feedback (DFB) lasers exhibited a minimum lasing threshold of 10.38 nJ pulse−1 (0.86 kW cm−2, 4.325 μJ cm−2) for Tr3. It should be emphasized that the ASE threshold of Tr1‐Tr4 was nearly unchanged from room temperature to 200 °C. The results suggest that this kind of truxene‐cored conjugated starbursts with high photostability and low lasing thresholds are rather promising gain media for organic semiconductor lasers.

By investigating a typical small molecule, 6,13‐bis(triisopropylsilylethynyl) pentacene (TIPS), the crucial influence of conjugated polymers as additives on modulating the crystallization processes, crystalline structures, and carrier transport is unraveled. The conjugated polymer additives including poly[2,5‐bis(3‐alkylthio‐phen‐2‐yl)thieno(3,2‐b)thiophene (PBTTT) and poly(9,9‐di‐n‐octylfluorene‐alt‐benzothiadiazole) (F8BT) via a solution crystallization method can bring in crystalline structures that are not accessible by nonconjugated polymers, demonstrating superior order and enhanced carrier transport without external treatments. In such cases, polymorphism of the small molecules is manipulated by the features of conjugated polymers in the blend. According to optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X‐ray diffraction (XRD), different crystalline morphologies such as fibrous crystals from TIPS/PBTTT and rod‐like crystals from TIPS/F8BT are observed, which is determined by the crystalline habitats and solubility of conjugated polymers in small‐molecule/polymer blends. Meanwhile, organic field‐effect transistors (OFETs) based on TIPS/PBTTT and TIPS/F8BT blends are prepared for the purpose of exploring the electrical characteristics, yielding the mobility of 0.3 and 3.53 cm2 V−1 s−1, respectively. The conjugated‐polymer‐mediated polymorphism of small molecules can provide an attractive platform to explore the fundamental relationship between crystal stacking and electrical behaviors without altering the chemical structure.