Qled devices, hole transport materials and producing methods thereof, and display devices

A method of producing a hole transport material, comprising:

• providing a precursor solution and a reaction solution respectively, wherein the precursor solution is used to provide at least a first metal source and a second metal source;
• adding the reaction solution into the precursor solution to obtain a composite compound of a first metal and a second metal after reaction;
• and
• heating the composite compound to obtain a polymer, wherein the polymer is a single nanoparticle comprising at least a first metal compound and a second metal compound, the first metal compound and the second metal compound are linked via a covalent bond or a Van der Waals force, and valence band energy levels of the first metal compound and the second metal compound are different.