Clarification of the Molecular Doping Mechanism in Organic Single‐Crystalline Semiconductors and their Application in Color‐Tunable Light‐Emitting Devices

Abstract

Organic single-crystalline semiconductors with long-range periodic order have attracted much attention for potential applications in electronic and optoelectronic devices due to their high carrier mobility, highly thermal stability, and low impurity content. Molecular doping has been proposed as a valuable strategy for improving the performance of organic semiconductors and semiconductor-based devices. However, a fundamental understanding of the inherent doping mechanism is still a key challenge impeding its practical application. In this study, solid evidence for the "perfect" substitutional doping mechanism of the stacking mode between the guest and host molecules in organic single-crystalline semiconductors using polarized photoluminescence spectrum measurements and first-principles calculations is provided. The molecular host-guest doping is further exploited for efficient color-tunable and even white organic single-crystal-based light-emitting devices by controlling the doping concentration. The clarification of the molecular doping mechanism in organic single-crystalline semiconductor host-guest system paves the way for their practical application in high-performance electronic and optoelectronic devices.

Organic multicomponent microparticle libraries

“…Notably, compounds 1 and 2 also possess similar molecular packing patterns and effective energy level matching (Supplementary Fig. 15b ), giving rise to color-tunable 12 alloy assemblies 52 , 53 .…”

“…For instance, we found that the combination of 3 and 4 can assemble into binary alloy ribbons with variable composition 30 . Moreover, the material combination of 1 and 2 which show a similarity in molecular configuration and size can also form two-component alloys by substitution of 1 with a small molar ratio of 2 52 , 53 . While the combination of compounds 1 and 3 or 1 and 4 , may result in heterostructured or isolated particles in their phase separated state due to their obvious structural differences.…”

“…The above results clearly reveal the alloy nature of 3 / 4 co-assemblies. Instead of using physical vapor deposition as previously reported 52 , 53 , we also modified the synthetic procedure of 12 alloys at y 2 = 0.1%, 1%, 10% ( y 2 = N 2 /( N 1 + N 2 )) by a drop-casting method. Similar to the case of 34 alloys, binary 12 alloys were also achieved (Supplementary Fig.…”

Precise Patterning of Organic Semiconductor Crystals for Integrated Device Applications

“…Organic semiconductor crystals (OSCCs) with intrinsic lack of defects and grain boundaries exhibit high charge transport efficiency, long exciton diffusion length, and lifetime, which has received ever‐increasing interest for optoelectronic device applications, such as organic field‐effect transistors (OFETs), organic light‐emitting diodes (OLEDs), organic photovoltaics (OPVs), and photodetectors . Over the past 30 years, impressive advancements in the carrier mobility of OSCCs have been achieved, as shown in Figure .…”

Effect of Substitution on the Hysteretic Phase Transition in a Bistable Phenalenyl‐Based Neutral Radical Molecular Conductor

“…The most common building blocks found in these compounds are those of phenalenyl and thiazole, as well as some others . Although substitutional doping has been explored in some molecular materials, most often as a means to control their optical properties for light‐emitting devices as well as some other examples, its application to molecular radical conductors is still relatively new. Recently, the Haddon group has been exploring the effect of substitutional doping on phenalenyl‐based neutral radical conductors .…”