Sang Myeon Lee

General Introduction

Historical Context

At the same time, toward the end of the last century, solid-state devices emerged as alternatives to vacuum tube-based electronics. Such a development led to the. Strictly speaking, these organic semiconductors had long been developed from the first discovery of electroluminescence on an acridine orange cellulose film in the early 20th century.1-3 Pope et al. From the 1970s onwards, the discovery of conductivity in doped polyacetylene, which has hydrocarbon chains with alternating single and double bonds, paving the way for the successful synthesis and controlled doping of conjugated polymers as the most important class of organic semiconductors, honored with the Nobel Prize in Chemistry to Heeger, MacDiarmid and Shirakawa in the year 2000.9 Since this initial discovery, extensive research has been conducted with largely two categories: doped and undoped organic semiconductors, along with various applications as conductive coatings or photoreceptors in electrophotography.

The beginning was the successful demonstration of an efficient PV involving a heterogeneous interconnection of p- and n-type materials, as well as the first fabrication of thin-film FETs from conjugated polymers and oligomers.10,13 However, the main impetus came from the top level. -Performance electroluminescent diodes from vacuum-evaporated molecular films and from conjugated polymers.7,8 Thanks to the great efforts of academic and industrial laboratories during the last decades, there has been rapid progress in OLEDs, leading at the same time to the first commercial production of products that include OLED screens.

Electronic Structure

Because of this trapezoid shape in the pz orbitals, the π bond causes very weak interaction by the shallow overlap of the π-electron cloud above and below the molecular plane. The 2pz orbitals perpendicular to the plane of the strand overlap and form π orbitals that extend along the conjugate chain. Therefore, there is a splitting of energy levels as the carbon number doubles.14-15.

For example, increasing the length of such bonds enhances charge transport behaviors with improved charge mobility through π bond systems.

Classification

Effect of the Fibrillar Microstructure on the Efficiency of High Molecular Weight Diketopyrrolopyrrole-Based Polymer Solar Cells. Further information on the fabrication of the device can be found in the Experimental section. The optical band gap was determined from the onset of the UV-vis absorption spectra in the polymer films.

Effect of poly(3-hexylthiophene) molecular weight on the morphology and performance of bulk polymer heterojunction solar cells.

Optoelectronic Applications: General Mechanisms

Organic Field-Effect Transistor
Organic Photovoltaics

Molecular Design and Engineering: Strategies for Electronic Uses

Required Properties for OFETs
Required Properties for OPVs
Material Synthesis Strategies

After the invention of transistors around the middle of the 20th century, inorganic semiconductors based on Si or germanium (Ge) began to take over the role as the dominant material in electronics from previously used metals.

Research Outline: Efficient Organic Conjugated Materials

UV photoelectron spectroscopy (UPS) was performed for the highest occupied molecular orbital (HOMO) energy levels of the two polymers, and the lowest unoccupied molecular orbital (LUMO) energy levels were found based on oak in the absorption spectra and HOMO energy levels. The relevant data for the as-cast films measured in this study are included in Figure 3.7.4 and Table 3.7.3. The representative current-voltage (I-V) characteristics of the annealed films are shown in Figure 3.7.5 and Figure 3.5.1a−c.

The devices based on the stepwise batches showed higher PCEs than those of the corresponding ones produced by the conventional method (Figure 5.7.10).

Furan vs. Thiophene as Flanking Group: Benign Electronics

Material Synthesis

Optical/Electrochemical Properties

Microstructural Analysis

Device Characterization

Solubility Characteristics

Conclusion

Supporting Information

Notably, the HOMO level of PFDPPTT-Si is slightly deeper than that of PTDPPTT-Si due to the relatively high ionization potential of furan.52. The film morphological characteristics of PTDPPTT-Si and PFDPPTT-Si were investigated using atomic force microscopy (AFM) with tapping mode. PFDPPTT-Si showed better solubility at room temperature in the tested solvents due to the large dipole moment of PFDPPTT-Si; in contrast, PTDPPTT-Si.

Solubility measurement: The solubilities of PTDPPTT-Si and PFDPPTT-Si were determined in the test solvents.

Motivation

Material Synthesis

Conclusion

The correlation length was extracted from the reciprocal value of the marginal spatial frequency PSD‒spatial frequency graph (Figure 3.7.2 and Table 3.7.2). Two-dimensional (2D)-GIXD images and the corresponding diffractogram profiles of thermally annealed films are shown in Figure 3.4.2, and their crystallographic parameters are summarized in Table 3.4.1. Therefore, in the following work, we mainly focused on the comparison of the crystalline nature and molecular orientation of the annealed films.

The static voltage transfer characteristics of the inverter exhibit sharp switching and high gain of ~54, as shown in Figure 3.5.1f. Effect of the alkyl spacer length on the electrical performance of diketopyrrolopyrrole-thiophenevinylenethiophene polymer semiconductors. On the other hand, we find that the VOCs of SM-XY-based ternary systems are almost constant with one of the binary reference.

In addition, TEM images (Figure 4.6.1b) show that the small molecule binary mixtures (ITIC:SM axis) exhibit larger clusters than those in the corresponding PBDB-T:SM axis binary case. The SM axis series was used as the third component of the PBDB-T:ITIC NF-OSC on the binary host platform. Critical review of the molecular design advances in non-fullerene electron acceptors towards commercially viable organic solar cells.

The Ð data for the polymers synthesized during the short reaction times (Section 10 and Figure 5.7.3a) confirm this speculation. As can be seen in the relevant GPC results (Figure 5.7.9 and Table 5.7.9), in all cases the stepwise polymerization produced the polymeric components with higher Mw and narrower Ð values compared to those of the corresponding ones obtained from the conventional method.

Conjugated Direction of Third Component: Operating Mechanism

Material Synthesis

Photoluminescence Properties

Conclusion

As shown in Figure 4.4.1b, the strong absorptions of the SM axis molecules around 400-550 nm complement the absorption valley of the host materials (PBDB-T and ITIC), which could potentially be beneficial in improving the photon harvesting ability of ternary mixtures. movies. The current density versus voltage (J–V) curves of the binary and ternary NF-OSCs with different SM axis contents tested in this study are shown in the figure and the corresponding device characteristics are summarized in the table. In contrast, the decreases in VOCs of the ternary components at the elevated fractions of SM-X and SM-Y of more than 20% may arise from their highly agglomerated properties with large ratios, as shown in Figure 4.8.4, taking into account the major phase separation with the host materials into unwanted transport channels.31-32.

Note that the slightly reduced EQE of the SM-XY-based device in the 550–750 nm region can be attributed to unfavorable morphology caused by the incorporation of SM-XY, supporting the above explanation for the steady VOC. However, for both the PBDB-T:SM-X and PBDB-T:SM-XY blends, the emission peak of PBDB-T still exists to some extent and is even stronger than that of the neat PBDB-T film which is excited at 460. nm (see Figure 4.8.14a). The PL spectra of the ternary blend films are displayed in Figure 4.5.1c; SM-X and SM-XY based ternary blend films excited at 460 nm exhibit exclusive emission peak of PBDB-T at 715 nm, while all emission wavelengths of the SM-Y based ternary film are significantly reduced.

To clarify the surface and bulk morphologies of the SM axis-based binary and ternary mixture systems, measurements were performed using atomic force microscopy (AFM) and transmission electron microscopy (TEM). These results suggest that the cross-type SM-XY induces a self-crystalline property regardless of the mixed compounds. All ternary mixtures show a similar smooth, fibril-like phase separation on the nanometer scale.

No obvious crystalline features with similar diffraction patterns occur in any of the SM-Y-based binary blends, compared to their presence in the corresponding regular films. High Mw values of the PTB7 polymer could also be obtained through temperature changes (80 and 100 °C) from the preference control step, but this approach negatively affected the Ð values (entries 12 and 13). The result of entry 19 obtained by conventional Stille polymerization was also included in the PSC performance evaluation for the sake of comparison.

Influence of the crystalline nature of small donor molecules on the efficiency and stability of organic photovoltaic devices.

Polymerization Methodology: Stepwise Heating Protocol

Conventional Stille Polymerization

Stepwise Stille Polymerization

Characterization

Photovoltaic Performance

Conclusion

It is worth noting that all the polymer fractions formed in the low-temperature step (60 °C) readily dissolve in the mixed reaction solvent (Figure 5.7.3c), indicating that the change in reactivity caused by their solubility problems , negligible. Therefore, we further investigated the effect of changes in catalyst concentration and amounts at a fixed temperature of 60 °C during the low-temperature ripening process (entries 14 to 18). Solutions of PTB7-based polymers in chlorobenzene/1,8-diiodooctane solvent (97:3 vol%) at concentrations of 12 mg mL-1 were used for polymer:PC71BM (1:1.7 wt%) blend solutions.

Post-Stille polycondensation of the extracted chloroform fraction noted in the above row was carried out with an excess of compound 1 under the same conditions for 12 hours. Jungho Lee,† Sang Myeon Lee,† Shanshan Chen, Tanya Kumari, So-Huei Kang, Yongjoon Cho and Changduk Yang*. Sang Myeon Lee,† Hae Rang Lee,† A-Reum Han, Junghoon Lee, Joon Hak Oh,* and Changduk Yang*.

Mingyu Jeong, Byongkyu Lee, Yongjoon Cho, Jiyeon Oh, Sang Myeon Lee, Jungho Lee dan Changduk Yang. Daehee Han, Jihoon Lee, Sang Myeon Lee, Jung Hwa Seo, Sung Heum Park,* dan Changduk Yang*. Yujin An, Jiyeon Oh, Shanshan Chen, Byongkyu Lee, Sang Myeon Lee, Daehee Han dan Changduk Yang*.

Junghoon Lee, A-Reum Han, Sang Myeon Lee, Dohyuk Yoo, Joon Hak Oh,* in Changduk Yang*. Sang Myeon Lee, Hae Rang Lee, A-Reum Han, Junghoon Lee, Joon Hak Oh* in Changduk Yang*.

Acknowledgement

Korean Version

Junghoon Lee, So-Huei Kang, Sang Myeon Lee, Kyu Cheol Lee, Heesoo Yang, Yongjoon Cho, Daehee Han, Yongfang Li, Byoung Hoon Lee,* in Changduk Yang*. Shanshan Chen, Sang Myeon Lee, Jianqu Xu, † Jungho Lee, † Kyu Cheol Lee, Tianyu Hou, Yankang Yang, Mingyu Jeong, Byongkyu Lee, Yongjoon Cho, Sungwoo Jung, Jiyeon Oh, Zhi-Guo Zhang, Chunfeng Zhang, Min Xiao, Yongfang Li in Changduk Yang * Jungho Lee, Eun Min Go, Satej Dharmapurikar, Jianqiu Xu, Sang Myeon Lee, Mingyu Jeong, Kyu Cheol Lee, Jiyeon Oh, Yongjoon Cho, Chunfeng Zhang, Min Xiao, Sang Kyu Kwak* in Changduk Yang*.

Jiyeon Oh, Sungwoo Jung, Mingyu Jeong, Byongkyu Lee, Jungho Lee, Yongjoon Cho, Sang Myeon Lee, Shanshan Chen, Zhi-Guo Zhang, Yongfang Li in Changduk Yang*. Yongjoon Cho, Sungwoo Jung, Sang Myeon Lee, Shanshan Chen in Changduk Yang* Kyu Cheol Lee, Na Gyeong An, Sang Myeon Lee, Jungwoo Heo, Dong Suk Kim*, Jin Young Kim* in Changduk Yang*.

Mingyu Jeong, Shanshan Chen, Sang Myeon Lee, Zhiwei Wang, Yankang Yang, Zhi-Guo Zhang, Chunfeng Zhang, Min Xiao, Yongfang Li dhe Changduk Yang*. Hye Jin Cho, Seok-Ju Kang, Sang Myeon Lee, Mingyu Jeong , Gyoungsik Kim, Yong-Young Noh* dhe Changduk Yang*. Dutta, Junghoon Lee, Hae Rang Lee, Sang Myeon Lee, Hyungju Ahn, Tae Joo Shin, Joon Hak Oh* dhe Changduk Yang*.

Junghoon Lee, Moonjeong Jang, Sang Myeon Lee, Dohyuk Yoo, Tae Joo Shin, Joon Hak Oh,*. Gyoungsik Kim, Kyu Cheol Lee, Jonggi Kim, Jungho Lee, Sang Myeon Lee, Jeong Chul Lee,.