从聚乙炔到现代有机半导体
在传统印象里，聚合物最典型的用途之一就是绝缘：聚乙烯、聚丙烯之所以可以包电线，就是因为它们的电子主要处在稳定的σ键中，已占据电子态和可接受电子的空态之间间隔很大，没有容易移动的载流子。但在20世纪中叶，人们已经逐渐发现，“有机物”和“导电”并不天然矛盾，一些小分子电荷转移晶体可以表现出很高电导率，低维有机导体甚至开始成为凝聚态物理的重要对象。人们感兴趣的是：能不能让一个真正的共价高分子骨架本身成为电子导体，而且能够像无机半导体那样主动调控它的载流子？
SSH模型
SSH模型——为什么一条聚合物链上的“缺陷”会变成一种新的电子准粒子？
Gaussian Disorder Model
一个电荷离开单条共轭链以后，进入一整块真实、无序的有机固体，它究竟怎么走？
band-like transport 与 dynamic disorder
第三章的 Bässler 模型给出了一幅很有说服力的图景：在无序有机固体中，不同分子或链段处于不同局域环境，因此它们的 site energy 并不完全相同，而是形成一个具有有限宽度的 DOS。载流子处在局域态上，通过 phonon-assisted hopping 从一个 site 移动到另一个 site；温度越低，越难从低能 tail state 逃出来，所以 mobility 通常下降。这个框架成功解释了大量 amorphous organic…
Topology in the SSH Model
The Su–Schrieffer–Heeger (SSH) model is the minimal one-dimensional lattice model in which band topology can be formulated exactly. Its structure is a bipartite chain with two sites per unit cell and alternating hopping amplitudes $t1$ and…
Nietzsche on Nihilism
For Nietzsche, nihilism is the historical condition in which the highest values lose their authority. Its origin lies within the structure of Western metaphysics itself. Christianity, Platonism, and later moral rationalism all taught human…
Detailed Balance in Single-Junction Photovoltaics
The Shockley–Queisser limit is the detailed-balance efficiency limit of an ideal single-junction photovoltaic absorber. Its derivation requires only a few assumptions: photons with energy above the bandgap are absorbed, each absorbed photon…
To Remain a Mind in the Age of AI
AI is changing the economics of knowledge. Information that once required hours of searching, reading, comparing, and remembering can now be retrieved almost instantly. As this process becomes easier, the intellectual value of simply…
Pattern, scale, and a simple equation
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