Chiral molecules play important roles in advanced materials and technologies owing to their unique chiroptical properties. How to design and construct the best chiral molecules with intrinsically strong chiroptical properties is still a great challenge since there is an intrinsic contradiction between the large absorption dissymmetry factor and oscillator strength. In this work, through a systematic theoretical investigation, it is found that chiral cylindrical molecules could overcome this problem through accumulating the electric and magnetic transition dipole moment along the cylindrical axis direction while canceling them in other directions. Among all the investigated structures, (M)-[8]CC2,8 is found to exhibit the best chiroptical properties with gabs of 0.71 and oscillator strength of 0.032. To the best of our knowledge, this is the best chiral molecule with both large dissymmetry factor and oscillator strength. Further increasing the repeating units, the gabs can even reach the theoretical limit of 2 for (M)-[28]CC2,8, together with a large oscillator strength of 0.134. The result offers the exciting opportunities for designing and synthesizing chiral materials with truly large intrinsically chiroptical properties toward real applications in chiroptoelectronic and chiro-spintronic devices.

Most of the reported chiral molecules exhibit small absorption dissymmetry factor (from 10-4 to 10-2). In this work, (M)-[8]CC2,8 is predicted to exhibit gabs up to 0.71 and oscillator strength of 0.032. To the best of the knowledge, this is the best chiral molecule with both large dissymmetry factor and oscillator strength. Further increasing the repeating units of (M)-[8]CC2,8, gabs can even reach the theoretical limit of 2 for (M)-[28]CC2,8.image