Toward Conductive Mesocrystalline Assemblies: PbS Nanocrystals Cross-Linked with Tetrathiafulvalene Dicarboxylate
Toward Conductive Mesocrystalline Assemblies: PbS Nanocrystals Cross-Linked with Tetrathiafulvalene Dicarboxylate
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DOI：
10.1021/acs.chemmater.5b03821
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发表时间：
2015-12-08
影响因子：
8.6
通讯作者：
Scheele, Marcus
中科院分区：
文献类型：
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作者：
Andre, Alexander;Zherebetskyy, Danylo;Scheele, Marcus
我们使用有机半导体四硫富瓦烯二羧酸酯（TTFDA）组装PbS纳米晶到导电介晶。密度泛函理论计算预测PbS 1 S（h）态和TTFDA HOMO之间的尺寸可调的近共振排列，具有形成空穴导电通道的潜力。我们测试这一假设与运输测量TTFDA功能化的硫化铅纳米晶体的不同大小，并发现一个显着的调制场效应空穴迁移率。光热偏转光谱揭示了不变的Urbach能量配体交换后，而进一步的表面改性胶体原子层沉积导致的间隙状态的密度的强烈增加。PbS-TTFDA中的空穴传输对这种表面改性异常稳健。我们的介晶的结构分析表明，TTFDA诱导一个定义的粒子间的间距，原子晶格的取向，和介晶晶胞内的角度。这项工作的结果铺平了道路走向导电介晶组装的混合半导体纳米结构的尺寸可调的传输特性。
We use the organic semiconductor tetrathiafulvalene dicarboxylate (TTFDA) to assemble PbS nanocrystals into conductive mesocrystals. Density functional theory calculations predict a size-tunable, near-resonant alignment between the PbS 1S(h) state and the TTFDA HOMO with the potential to form a conductive channel for holes. We test this hypothesis with transport measurements on TTFDA-functionalized PbS nano crystals of different sizes and find a pronounced modulation of the field-effect hole mobilities. Photothermal deflection spectroscopy reveals unchanged Urbach energies after ligand exchange, whereas further surface modification by colloidal-atomic layer deposition leads to a strong increase in the density of in-gap states. Hole transport in PbS-TTFDA is unusually robust against such surface modification. Our structural analysis of the mesocrystals suggests that TTFDA induces a defined interparticle spacing, the orientation of atomic lattices, and the angle within the mesocrystal unit cell. The results of this work pave the way toward conductive mesocrystalline assemblies of hybrid semiconductor nanostructures with size-tunable transport properties.