Lithographical Fabrication of Organic Single-Crystal Arrays by Area-Selective Growth and Solvent Vapor Annealing

In Situ Raman Spectra and Machine Learning Assistant Thermal Annealing Optimization for Effective Phototransistors

The relationship between the structure and function of condensed matter is complex and changeable, which is especially suitable for combination with machine learning to quickly obtain optimized experimental conditions. However, little research has been done on the effect of temperature on condensed matter and how it affects device performance because the difference between the in situ physical property parameters (which are lowered by the surface tension and mixing entropy) and the basic parameters of the bulk makes accurate AI predictions difficult. In this work, P3HT/ITIC was chosen as the donor/acceptor material for the active layer of organic phototransistors (OPTs). The thermal annealing process has been detected by DSC, UV, and Raman, where Raman can catch the lowest critical phase transition temperatures and give the best raw data for exact machine learning. An accurate and reliable model was developed to predict and screen the optimal annealing temperature at 110 °C for OPTs to reach maximum Dshot* values of 3.51 × 1012 Jones with low power consumption of 54 pJ. This study provides a new idea for the in-depth exploration of the mechanism of the effect of temperature on condensed matter to achieve the precise regulation and optimization of the performance of organic optoelectronic devices.

Organic Semiconductor Single Crystal Arrays: Preparation and Applications

The study of organic semiconductor single crystal (OSSC) arrays has recently attracted considerable interest given their potential applications in flexible displays, smart wearable devices, biochemical sensors, etc. Patterning of OSSCs is the prerequisite for the realization of organic integrated circuits. Patterned OSSCs can not only decrease the crosstalk between adjacent organic field-effect transistors (OFETs), but also can be conveniently integrated with other device elements which facilitate circuits application. Tremendous efforts have been devoted in the controllable preparation of OSSC arrays, and great progress has been achieved. In this review, the general strategies for patterning OSSCs are summarized, along with the discussion of the advantages and limitations of different patterning methods. Given the identical thickness of monolayer molecular crystals (MMCs) which is beneficial to achieve super uniformity of OSSC arrays and devices, patterning of MMCs is also emphasized. Then, OFET performance is summarized with comparison of the mobility and coefficient of variation based on the OSSC arrays prepared by different methods. Furthermore, advances of OSSC array-based circuits and flexible devices of different functions are highlighted. Finally, the challenges that need to be tackled in the future are presented.

Chaotic Organic Crystal Phosphorescent Patterns for Physical Unclonable Functions

Since the 4th Industrial Revolution, Internet of Things based environments have been widely used in various fields ranging from mobile to medical devices. Simultaneously, information leakage and hacking risks have also increased significantly, and secure authentication and security systems are constantly required. Physical unclonable functions (PUF) are in the spotlight as an alternative. Chaotic phosphorescent patterns are developed based on an organic crystal and atomic seed heterostructure for security labels with PUFs. Phosphorescent organic crystal patterns are formed on MoS₂ . They seem similar on a macroscopic scale, whereas each organic crystal exhibits highly disorder features on the microscopic scale. In image analysis, an encoding capacity as a single PUF domain achieves more than 10¹⁷ on a MoS₂ small fragment with lengths of 25 µm. Therefore, security labels with phosphorescent PUFs can offer superior randomness and no-cloning codes, possibly becoming a promising security strategy for authentication processes.