Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Phys Rev Lett. 2009 Nov 27;103(22):226401. doi: 10.1103/PhysRevLett.103.226401. Epub 2009 Nov 23.
"Noncompensated n-p codoping" is established as an enabling concept for enhancing the visible-light photoactivity of TiO2 by narrowing its band gap. The concept embodies two crucial ingredients: the electrostatic attraction within the n-p dopant pair enhances both the thermodynamic and kinetic solubilities, and the noncompensated nature ensures the creation of tunable intermediate bands that effectively narrow the band gap. The concept is demonstrated using first-principles calculations, and is validated by direct measurements of band gap narrowing using scanning tunneling spectroscopy, dramatically redshifted optical absorbance, and enhanced photoactivity manifested by efficient electron-hole separation in the visible-light region. This concept is broadly applicable to the synthesis of other advanced functional materials that demand optimal dopant control.
“非补偿 n-p 共掺杂”被确立为一种可行的概念，通过缩小 TiO2 的带隙来增强其可见光光活性。该概念包含两个关键要素：n-p 掺杂对之间的静电吸引力增强了热力学和动力学溶解度，而非补偿性质确保了可调谐的中间能带的产生，有效地缩小了带隙。该概念使用第一性原理计算得到了证明，并通过使用扫描隧道光谱学直接测量带隙缩小、显著红移的光学吸收以及在可见光区域有效实现电子-空穴分离的增强光活性得到了验证。该概念广泛适用于其他需要最佳掺杂控制的先进功能材料的合成。
