14. Let \( f(x) = A(x^2 - 2x)e^x - e^x + 1 \). For any \( x \leq 0 \), \( f(x) \geq 0 \) holds. Determine the range of the real number \( A \).
When $x=0$, $f(x)=0 ; x>0 \Rightarrow p^{\prime}(x)$ is monotonically increasing, and $p^{\prime}(0)=0 \Rightarrow p^{\prime}(x)>0 \Rightarrow g^{\prime}(x)>0 \Rightarrow g(x)$ is monotonically increasing, thus $g(x)<\lim _{x \rightarrow 0} \frac{1-\mathrm{e}^{-x}}{x^{2}-2 x}=\lim _{x \rightarrow 0} \frac{\mathrm{e}^{-x}}{2 x-2}=-\frac{1}{2}$.

In summary, the range of real number $A$ is $\left[-\frac{1}{2},+\infty\right)$.